I added GeckoLib correctly to my build.gradle and everything works except for the resources. When I try to load a world the game crashes because it can't find the geckolib3:geo/creeper.geo.json file, I attached the debug log for more information
debug.log (MC 1.18)

That log doesn't have a crash in it. Reload the game and test again.

I get this error everytime I launch the game in IntelliJ

I cant find line I mean in the log so here it is software.bernie.geckolib3.geo.exception.GeckoLibException: geckolib3:geo/creeper.geo.json: Could not find model. If you are getting this with a built mod, please just restart your game.

Congratulations you found the cache bug thats 1 out of 1000 launches and is unfixable.

Update to 1.18.1 and update the mod. Read the wiki for the changes to the name. Works fine in Eclipse for my own mods as well.