I think this was said before the announcement to get people speculating.

Not much has been said about the new divinity but from my understanding, divinity was a series of games made by larian before divinity original sin with a much darker tone and more similar to an arpg than a turn based rpg like original sin or baldurs gate 3, but who knows which type of rpg the new divinity will be. My guess is turn based because that is what they are known for due to the success of bg3.

I think they are in the same universe. One look at larian's games on steam tells me they just don't know how to name games properly.