Hi, it seems that you have created one of the best mods for the new planet. I discovered that if I create a new game in the sandbox, immediately go to Carna, and use the console command to open 4000 map chunks (approximately how many can be opened in the late game), after the map opens, on my new computer with an Intel Core i5-13600 processor, the UPS drops to 28, which seems like it shouldn't be normal. Here is the command, just in case:

/c local radius=4000
game.player.force.chart(game.player.surface, {{game.player.position.x-radius, game.player.position.y-radius}, {game.player.position.x+radius, game.player.position.y+radius}})

Carna nor its design takes into any account on using player commands to do anything, it relies on natural game generation, otherwise it may result in objects not spawning and breaking mechanics or freezing and corrupting your world. You're best not using commands when playing the game is the best I can tell you, I have no way of fixing this.

UPS may take an impact when naturally generating chunks, but this is due to the number of objects spawning tiles, it goes away after generation is complete.

This command does not do anything special; it simply reveals the map, just as a player would. I like to play with reduced resources and use this command to check if there are any problems with their generation. On other planets with enemies, UPS does not decrease from this; it seems that something is wrong with some objects, possibly enemies, which for some reason consume a lot of UPS.
In this case, the only possible option for playing Carna is to increase the amount of resources when creating the world in order to minimize the need to explore the map, otherwise the UPS will gradually drop even on good computers.

It is not the enemies, it is likely the beacons that are generated from every chunk being spawned. I have no experience doing anything with playing with commands, so I can't really do anything about this, I only ever play the game normally without the usage of commands, but I can ascertain that there is a significant difference in result when spawning the chunks on Carna normally vs using the command and the command results in various things not generating on Carna normally.

My small experience of Carna play say that amHunter is right. At first we slowly scouted map, later we used artillery to clean all enemies that were in range of manual fire. Explored radius was way bigger than any healthy base could require. We have sometimes ups drops, but we use giant mod pack, but still we are almost always at 60 UPS.
This is best looking planet ever. I even didn't want to deconstruct ruins, they are so cool.

The UPS issue is caused by the wandering behavior of the maintenance units.

I did a flame graph profiling, in the mod pack server I am playing on. Out of 156 samples related to Carna:
- 130 of them are in Unit::update
-- of which, 128 are in Unit::update -> Commandable::runBehavior
--- of which, 89 are in Unit::update -> Commandable::runBehavior -> WanderBehavior::executeInternal
---- of which, 20 are in [...] -> Unit::lookAhead, 28 in Unit::calcSeparation, and 32 in Unit::move

(For a comparison, Carna's Lua code accounts for only 8 samples)

And when you compare it to other planets, Carna costs about as much as than these modded planets combined in our save: Castra (65 samples; the planet also has a Unit wander issue, but much fewer units are on the map with similar size of the map explored), Rubia (39 samples, the planet is known for heavily optimize the trashsteroid calculations), and Muluna (56 samples, the planet where most of the science are being produced in the save)

Also I should mention, in several modded planets, for example, Tenebris and Nix (from Metal and Stars mod), the UPS cost from units can be mitigated by killing all of them on the map with a remote spidertron, but for Carna maintenance units, they are not considered enemies and I would really prefer not to manual target every kill, assuming it is even possible

I can see about adding an option to simply have them die off, I am worried that marking them as enemies would make them probably act strangely. I'll see about handling this though.

I have given the bots an "expiration" timer, in short their healing per tick will kill them off after a short amount of time. There is an option included for those that like the bots like myself to not have them expire and keep them around. This option is safe to toggle on and off mid save.

Thanks!