Ive tried a few overhaul mods lately, the last being IR3 (which i could only endure for ~90 minutes).

This one had by far the best first hour of all of them.
Starting with no recipes means each new unlock is a relatively large amount of new stuff one can do
and with the early tech taking seconds to complete you can ration those new unlocks yourself.

Im now 7 hours in, just unlocked the Steel parts, the second Plastik recipe and basic Alu.
Its started to stop being fun a while ago. Tech is now 2+ minutes, more labs are still far away
and each new tech is just a small amount of new recipes compared to whats already available.

Most of the early game being based entirely on fluids is ass. Handling fluids isnt fun
and i expected to get away from that eventualy. But im unlocking more fluid stuff every tech.

When i saw how expensive buildings are i naturaly expected to only need 1 or 2 of each.
But im looking at lines of several ChemPlants per product.
And now i have the recipe for the Furnace2 which is pointless. Its insanely expensive to make but is only eactly twice as good.
With no enemies having more compact buildings isnt worth much.

The recipe for belts making 15 at a time seems awesome until you realize that 90%
of things are fluids. And pipes are expensive and slow to produce. Except for the Pipe2 because Plastik is dirt cheap.

I have 2k pipes sitting around which i cant upgrade because for some reason
every building requires the previous version, except for pipes.

New recipe for the same product:
One would expect that a new recipe means to which to immedietaly.
For crushed Iron Ore that not hard to do but its also not very rewarding given how little Iron is need for research.
With Plastik 2 it requires a complete rework of the Facility which i can put of for hours given the amout i have stockpiled.

Byproducts:
Conceptualy i like the idea of recipe having secondary outputs.
But so far all that does is require me to set up dumping instead of being an interesting circular process.

Making steel make CO2 but so little of it thats its not worth dragging a pipe back through half the base instead of just venting it
and making large amounts of new CO2 for free and cheap from thin air.

I need amounts of H2 so im electrolizing water and venting 90% of the O2 made.

Im dumping both Caustic and Brine after collecting multiple tanks of each and waiting for a recipe that uses them.

Soon im going to have to start dumping stone somehow. I dont understand the logic of having the brick recipe make more bricks that it uses stone.
Stone are not used in any recuring recipe. The are simply a byproduct with no other use than to be voided with extra steps.

Why not for example have a process that combines stone with Hydrochloric acid to produce H2 and Mineral sludge, which can then
be filtered for a small chance to gain ore and minerals while getting back some Chlorine and/or Mineralchloride.

So far by big problem with this mod really comes down to the "all fluid" thing.
After 7 hours i still havent automated science because its pointless.
A chest full of Ore makes hundreds of Mineral samples, i have 600 climate samples in stock because why not
and the Mechanical samples require a motor which is far too complicated to automate at this point.
The occasional handfeeding of 2 Assemblers takes way less time than automating that stuff all the way from the Furnace.

With the tiny amounts needed at every step and the uber linear nature of the techtree
i would just handfeed Assemblers to get past things like "make 20 Rubber" or "consume 200 Mineral Dust".
But none of that works with Fluids. You have to set up multiple ChemPlants and Pipes only to unlock a new recipe
shortly after you are done.

What isnt helping is the huge amout of Icons in the production tab that all look the same.
Every Gas recipe is either Blackredwhite or BlueWhitePurple with tiny Indicators far too small to matter
so you constantly have to mouse over just to check wether you are selecting the correct recipe.
Since none of these recipes can be crafted by hand they all have a red background.
Instead of the flaming Symbol make one Big 1-2 Letter Sign for the main Product and then have the Corners be small letter shorts for the
Ingredients colored in such a way that they Clash hard with the red background.

The 4 valves all look the same with slight variations in color instead of making them Arrow based pictograms.
The have the same problem. Unless you mouse over you cannot differentiate them, which is really bad

And i assume this will get worse the further in you go.
It not just yours, many mods have this problem with shitty non-descript icons using washed out brown-grey palettes.

Nullius is designed to reward continually automating and scaling up. If you neglect to do so, it will feel slow and tedious. At the technology level you have reached, the factory should be able to run unattended until it fills its output chests with power poles, belts, pumps, tanks, and so forth. It seems that you're seeking a mod that doesn't ask that of the player. There are other mods that may better suit your interest.

But thats the thing. There is no point in automating up because there is nothing in sight that i would need it for.

I have a Lab and a few assemblers running somewhere with the only non-trivial input being some plastik
and with 3k of that stored away i can savely disassemble my setup to make room for the level 2 plastik recipe.
I cant research faster because you cant build more labs.
Many of the builds are unfun to lay out because its all fluids.

I played about 8 hours and for the last 2 my base felt meaningless.
I was building stuff for the sake of building stuff. I made rubber only to find that the only thing that uses it is the next level of armor
(and chests yay) which is pointless without more stuff to put in.
I could automate steel gears and aluminium wire but without anything that uses them why would i.

I design stuff back to front.
Making items just because i can, without any idea where, when
or in what quantities i might need them makes no sense.

If not knowing what to plan for was your only complaint, I'd recommend playing https://mods.factorio.com/mod/nullius-momenti-modpack, which includes Recipe Book among other must-have mods. But you seem to dislike nearly everything that Nullius is fundamentally about (avoiding handcrafting, dealing with complicated fluid recipes and byproducts, deciding which recipes to use where and when), so I doubt it will of much use.

I do use recipe book. But only for things i already researched.
If i wanted to look ahead on tech or crafting i might aswell just watch someone play the mod.
That would give me the same spoilered experience without having to put in all the legwork.

Avoiding handcrafting only makes sense once it actualy saves time.
Setting up automation takes a while especialy without logistics.
Meanwhile clicking the crafting queue takes seconds. The actual crafting is free
since you spend many minutes standing around planning anyway.

Complicated recipes are fine. Complicated fluid recipes galore is not.
Fluid are simply way less fun to build around than solids.
There is nothing inherently better or more difficult about fluid recipes. But there are more root inputs involved in setting them up.
Even just being able to stash a batch of something in a chest for a while is so much nicer
than having to decide between pumping a few tanks full of liquid out of the way
or just deconstructing them and wasting the content. Usually i do the later.

I love the idea of dealing with Byproducts but:
I ground up sandstone by the double-dozen to make the hundreds of undergrounds needed for the chemplant orgy.
Then i got the glass recipe (more sandstone) to make more chems, which i set up.
I then did other stuff, meanwhile a chest full of glas accumulated.
I had just sated my need for sand for the forseable future.
Then i unlocked Aluminium, which almost made me ragequit and that was the beginning of the end.

The first recipe with a byproduct and the first recipe with that product as its main ingredient
ought to be next to each other in the tech tree.
This is not nessecary for the entire mod but certainly early on to encourage people to
interconnect production chains right away.

The Alu process creates crushed iron aswell, which you would stash.
Shortly thereafter Iron1 would be in the techtree giving you the Aha! .
Not only better Iron smelting but also a way to deal with the byproduct of the
chain you just finished setting up creating a nice flow in the early game recipes.

A byproduct should come in before its main recipe.
Which is hilarious because thats exactly what the mod is doing with all the fluids.
The Fluids which you are dumping by the truckload early on because there is no use for them.
Suddenly, with the first real solid chain, it does not.

After playing other stuff for a while ive now come back to give this mod another try.
Im looking for someone mildly experienced who'd be willing to take a look at my 8 hour savegame
(maybe even over Discord with Voicechat) because im still convinced that im missing something.

I have this convoluted mess of electrolyzers and chemplants turning Brine into Chlorine and eventualy, together with Caustic, into Saltwater
with a small amount of Plastik being created inbetween almost accidentaly and the whole setup feels like a joke.
This cannot be how this is intended, i must be making some dumb mistake somewhere.

So far (just starting green science) it feels like you never want to use recipes that combine caustic and acids. If you are, you're either running your brine electrolyzer when you don't need to, or you missed a key recipe. You said you're mixing caustic and chlorine to get saltwater... you're not doing that AS a source of saltwater, right? (You did ask about dumb mistakes...)

I create a lot of brine doing sea->salt->pure water, electrolyzing the pure for hydrogen, and electrolyzing the brine for chlorine & hydroxide, dumping the brine if I don't need either chlorine or hydroxide. It seems very important to have a way to get rid of any individual byproduct you get too much of, and stop production on that set of machines if you don't need the primary product.

For example, here's how I set up my brine electrolyzer so that it only runs if I need one of the two products. I put these items near each other: a large chest to hold hydroxide, my chlorine tank, and the belt feeding hydroxide to the chest. Then I split the belt and used two of my starting red wires to one of the belt segments after the splitter to the chlorine tank and the other to the hydroxide chest, and gave them a condition to check to see if that resource was low (hydroxide < 4k, chlorine < 5k). Then merged the two belts back together. This way, my hydroxide belt (and thus my electrolyzers) run if need at least one of the outputs, and the belts back up and the electrolyzers stop if I have enough of both resources.

Similarly, you start getting some chemical reactions that output useful byproducts. To make use of them (like CO2), what I did was have a primary output Tank2 with a pump leading out to feed the factory, and a pump leading directly in to return the byproduct, with two different lanes on my fluid bus - one for CO2 heading into the factory and one that's returning CO2 byproducts from different parts of the factory. Then I connected a separate tank to the main one via a top up valve, and pump into that tank from the machines making CO2. So it was Distiller -> pump -> production tank -> top up valve -> output tank. This way you leave a lot of space in your output tank for byproducts to flow in, keeping those lines from clogging up. And a relief valve on the output tank lets you void if you have too much in your output tank.

If that all sounds like hell to figure out, I think this probably isn't the right mod for you. It was almost too much for me to deal with, but I kept going and figured out a few strategies for dealing with those things.

Organic chem 1 & 2 significantly increase your plastic output, and you're using mostly hydrogen and air instead of chlorine.

I did play for another 8 hours and i just reseached Pumping 2.
I guess my bigest mistake was assuming that, since the mod doesnt give you any proper tools (read: Combinators)
for hours, the recipes are set up to just work with the primitive Valves. Now that i have the Combs
i can finaly set up proper double or triple conditions for turning on the Brine Elecs.
Yes, i did run those flatout most of the time, because u couldnt be bothered trying to figure out
how to not do that with the Valves.

Another issue was that since you dont need any Alu before the Purple science my consumption of Caustic was essentialy zero.
Now that im using Alu more often that problem has largely solved itself.

Realisticaly i should have just modded the research to get the combinators way earlier.

Elec3 will allow splitting of HCl Gas which should have come way earlier.
I hate how the mod makes you set up several songs and dances only to give you a recipe 5 hours later that makes you rebuild everything.
I expect to be done with parts of my base after a while.
If a mod does that then both Construction and Logicstic bots should be unlocked way sooner.
If i could stand there like a conductor with a stocked up botmall instead of running around like a Peon this would more bearable.

CO2 is a bad example of a byproduct. The steel production and the Air separators are on opposit ends of the base,
i already need to drag an Oxygen pipe there. Draging a pipe back when CO2 can be created endlessly for almost free is pointless.
I hava an army of pipes runnuning cross everywhere.
I hate fluids.
I want to use belts again, not just to sends a handful of things to the Labs.