The original Baldur's Gate 3, called "Baldur's Gate 3: The Black Hound" which got cancelled years ago, would have had absolutely nothing to do with the first two Baldur's Gate games either. On top of that, that game was going to be set far away from Baldur's Gate, in the Dalelands.
Why do you think it got cancelled? Because BG3 didn't need to be made. It really still doesn't.
Baldur's Gate: Cult of the Damned
Baldur's Gate: Avernus
Baldur's Gate: Ilsensine
or many other options would have been better than BG3, which sets up entirely different expectations.
I doubt it would have made a difference to use those names because Baldur's Gate would still be in the title so people would immediately apply expectations on the game no matter what.
Not that it matters. Many game franchises have changed setting, time periods and protagonists between games. Every Final Fantasy and Dragon Quest game. Red Dead Redemption to Red Dead Redemption 2, which turned into a sequel and a completely different protagonist. The Dragon Age games went from fighting a Blight in Ferelden as a Grey Warden to being the Champion of Kirkwall, fighting Qunari, mages and templars to becoming an Inquisitor and fighting a bunch of demons and a darkspawn magister.
"I used my last magic poo to check in on my daughter." Scanlan Shorthalt.
