Hey,
would it be possible to add support for some gleba-specific sprites? I'm having a really hard time identifying Yumako trees for example, as the fruits just blend into the background, or telling from the map screen what's water and what's not (not sure if that part is intended though)

Thanks for the suggestion! Are there other sprites you have trouble with? I must admit I still haven't built a Gleba factory yet, so I have no personal experience to draw from.

If the Yumako fruits are the only difficulty, then it should be simple to add a color picker that would adjust the color of the fruits.

or telling from the map screen what's water and what's not (not sure if that part is intended though)

This is an interesting request, as it is actually possible to modify the color that tiles appear on the map. (For example https://github.com/wube/factorio-data/blob/2365bf12bf9ef4cc1c6cd50f430c9f88b298af63/space-age/prototypes/tile/tiles-gleba.lua#L128). The trick is figuring out how to fix it. There are 45 different tile types on Gleba, and exposing a color setting for each of them would be completely impractical. Maybe you are trying to say you only care about tiles that players can't walk on? In that case, "gleba-deep-lake" is the only Gleba tile that matches that, so I could add a color picker for that tile's map color.

I'm also just beginning on Gleba, so for now the most noticable thing were the Yumako fruits. I took a look at the files and it seems like there's actually a "normal" a "harvest" sprite, I assume these are picked based on whether the tree is ripe for picking? Not like I can tell lmao.

45 different tiles is definitely not feasable, but the deep lake is not a problem, at least for me. What was more difficult is distinguishing the buildable terrain for the harvestable plants from the marshes that have the same color, but turning off the new "Additional terrain effects" graphics setting in 2.0.21 actually helped in that regard. The settings is meant for performance reasons but also changes how buildable terrain is rendered.
I think where my original request came from, was that I took to the map screen for help, since I couldn't tell what was water and what wasn't, but that didn't do much. I actually got used to how the map looks now and can tell things apart better after disabling the new setting.