Then by those stipulations, BG3 isn't a D&D game. Because it uses Larian's homebrew.
But it *feels* somewhat like a pen-and-paper roleplaying game. You can’t do everything, but you can do a lot, and you see and feel the dice roll.
And while D&D reigns supreme in the USA, in Europe there is a lot more variety of RPGs.
At a meeting of mostly p&p roleplayers end of last year, almost all had played BG3, but most didn’t actually play D&D.
So there are a lot more than just the D&D players who are interested in the game due to being a well-made RPG.