OP is correct and not correct.
BG3 is a faithful representation of DnD 5e. Not perfect, but easily as good a representation of the system as any other game.
DnD 5e, however, is simply a bad system compared to previous ones. You have way less power potential, way less customization, way less specialization, way less build diversity, everything is simplified for non-DnD players at the expense of DnD players.
It's not Larian, it's DnD 5e.
