Hey bro, Due to user demand for a relationship between the skill tree and items, I'll be adding the following improvements in the next update:
I'll create a Tag for Items, so that when you use them you gain the designated LP.
I'll create the same TAG for enemies, so that when you hunt specific enemies you gain LP.
And I'll add a level-related gain curve system to the editor.
This update should be released within a week; if you want, I can let you know when everything is ready.