I find that the pure amount of sand you need to keep everything operational is a bit crazy.

For a system which isn't even that large I have to have 5 belts of advanced belts full of sand.

https://i.imgur.com/2jTmg6Q.png

Without sand you can't make glass, silica and Chlorine which means translates no rare metals, no electronic components.

This seems compounded by the fact that most the the stuff that consumes sand doesn't take productivity modules.

I think it's a good idea to use every resource in the game, some more some less. You even need uranium-238 for prod. science, unlike vanilla Factorio where almost no stone or uranium is needed.
Please, don't nerf this, diversity is good here.

I am not saying to remove it, just tweak the numbers a bit. One example of this would be lower sand input for machines (glass, electrolysis, quartz) and instead increase stone input for crushers.

And this is the good example of variety, some resources need more space, belts or bandwidth. There is no fun when everything is balanced, when you consume the same amount of different resources, when you can solve a puzzle in minutes and just copy-paste a balanced solution.

You can use trains if you need more bandwidth.

but more than 5 belts worth for not even a full belt of stone going in? come on...its numbers are way out of wack.

There's no issue. You don't have to use belts to transport the sand, look at it the same way as copper cable, where it's best practice to transport copper plates and then direct feed cables wherever possible. The recipe for sand is 3 stone for 7-8 sand, that's 2.5x expansion, you can account for that before you plan your setup.

I agree with monaut, it is generally advisable to put the compressed resource on the belt and expand where you actually use it. so you could replace your five sand belts with two stone belts.

you also get a lot of sand from processing immersite. I think it's fine.