To start with, a gleba start is pretty rough on burnable fuel. I might be missing something, but:
1) The fairly high cost of research to get heating towers, rocket fuel, and electric furnaces makes for a fairly long, pretty nasty 'burner' phase.
2) The best option is burning unprocessed fruit but of course you'll be seed negative doing that.

When you combine this with the incredible cost of military science, how incredibly ineffective handheld rockets are at killing stompers, you spend a really, really long time (several hours) 'trapped' in a starting area having to be extremely careful with your pollution cloud until you finally get some efficient power generation and a tank to deal with medium stompers that show up shockingly early now.

It's all mostly doable, just very, very slow and tedious. The biggest problem is the typical science rate of 45/minute for military science would require six full belts of spoilage (coming from... nutrients maybe? Eventually you could do nutrient recycling.) and a whopping 75 biochambers to burn it into carbon.

I modified the grenade recipe to take 1 explosives instead of 10 coal to make it possible to do military research without going crazy. I know you don't want to make too many changes other than fixing softlocks, but that might be one worth considering. I'm not sure what would be a reasonable change to improve the starting power situation. Maybe modify more of the trees to drop wood? Or add big rocks with coal in them?

I have received some suggestions to make Gleba a little more bearable for the average player, and I've been thinking about moving heating towers up in the tech tree (which I think someone else has suggested as well) to solve some of the burner phase pains. Pentapod eggs are actually a pretty good power source early on (6MJ) if you're just the right amount of crazy to pull that off, it's actually quite fun.

Regarding military science though, yeah, it's a bit rough. I'm not sure what to do to improve the coal requirement, I don't want to add or change any recipes as I'm sure you know, but it's not like there's any technologies that make it better that you don't have access to normally besides maybe the recycler, but I don't think it would be right to move that from Fulgora. I think the best thing to do is just rush to space, get a very minimal space platform up, and send down all the carbon you get from up there to boost what you're making on the surface. If I can think of anything else to change I'll probably do it, thanks for the feedback.

IMO there's, no need to move up heating towers up the tech tree. Steam engines are good enough for a good while. As for fuel there's tons of different options, I would recommend searching a bit more for the optimal one.

Coal for grenades is a bit of a drag. But don't need that much military science. In my run I ended up using only personal rocket launcher and land mines for combat.