Sorry but I just basically disagree with everything you said there. It just kind of seems like you want to knit pick ANYTHING that isn't 5e. The game is "based" on 5e, that doesn't mean it has to be a 1:1 carbon copy of it. Why would a video game limit that much and probably limit its playerbase to just D&D nerds (and I mean that in the best possible way, I was one for years). If they did that, and did not add some other flavor to the game, it would turn off more players than draw in. Not to mention, there is even a good number of D&D players that despise 5e. Just saying.
It doesn't need to be a 1:1 copy, but what Larian apparently doesn't realize (or ignores) is that modern D20 games have a very narrow range of values where every +1 matters. That also means that many rules have a mathematical reason to be what they are instead of just being limited by humans having to calculate everything.
That of course clashes with Larians preferred way of designing games which is flashy and throwing out bonuses like candy. Mixing those two approaches creates a huge mess which sadly is currently seen in BG3.
