All they did was graft whatever 5e rules would fit on the DOS2 engine, adapted a few rules to jury-rig DOS2 features in to the game, and then threw the rest out in favour of DOS2 mechanics.
BG3 is just a heavily modded DOS2.
BG3 feels like neither BG nor D&D, but it sure feels a hell of a lot like DOS2.
You've obviously not played much in DoS.
Because I didn't like it?
You can lie to yourself all you want, but the similarities between BG3 and DOS2 are glaring, and far more apparent than any connection to the previous BG games.
I was supposed to write a post comparing BG3 and DoS2 but from what I see it won't make much sense.