I have some ideas on how to balance SimplySkills for my modpack. It would be nice there was a way to tune the values in the skill tree through config files, since things can get quite OP. Particularly I would like to decrease the Max HP% nodes since my tank managed to get 200 hearts by stacking flat hp (we are still dying to DAS).

Old pic (before gems)

Can't you do this with datapacks? See puffish skills docs

I think I can, I was able to find each node inside data/simplyskills/puffish_skills/categories/tree, just trying to figure out how to edit those values via a datapack

Hey 👋
As you've already mentioned, creating a datapack to modify the values will work. You will just need to crosscheck it against new version of the mod, whenever you choose to update.