Probably depends which Baldur's gate you mean, I'm guessing you are referring to Baldur's Gate dark alliance, both that and Diablo are real-time games, whereas Divinity: Original Sin 2 is a turn-based strategy game.

Now if you like the turn-based fighting in Dragon Quest 11, you might get along with D:OS2, but I'd probably recommend watching a few video reviews and a few playthroughs before diving in.