Neither the story, nor the game-engine, has anything to do with the game Baldur's Gate. Unless they decide to slap the Bg name on the cover, it's not Baldur's Gate 3.
/me shrugs helplessly
..
.. snif.. .. ..
Which they were going to do since Black Isle only had the rights to publish D&D RPGs with Baldur's Gate or Icewind Dale on the cover. Now they can't even publish Baldur's Gate on the PC and probably not Icewind Dale either.
Without knowing the entire story, it's hard to say that there wasn't some tie ins into the first games somewhere into the game.