The notion that it is a homebrew that Wizards can learn any spell is utter nonsense. Think about it: ALL other casters have a restricted list of spells, related to their class, BUT suddenly the Wizard can learn them all. WTF. It does not hold water.
I accept that Larian has its own version of D&D, that BG3 is its own thing ... but don't act like it is normal that the Wizard has this super-feature, while all other casters do not have access to all the spells of a given level.
nb : I played a Wizard and just refused to learn non-Wizard spells by principle. I can already hear the usual response: well that is your choice, an option... which is not the f..... point! Saying the Wizard-learning-any-spell from scrolls is normal or not broken is just utterly stupid.