Nothing about that quote implicitly suggests which type of combat system the game will have.
I think that you two associate Larian with TB more than they do, themselves. Larian made two TB games, D:OS 1 and 2, and a lot of games before that which didn't use TB.
There are a lot of ways in which Larian's Baldur's Gate is pressed to live up to expectations, not the least of which is the writing - and there was some concern over who is working on the writing for BG3 and their past style of writing. There's also the combat. There's also things like world building, and other things.
Larian's "type of Dungeons & Dragons" isn't about a particular combat system that we know of. Larian hasn't made a D&D game before.
Personally, I don't see how a game could be authentically Baldur's Gate withotu RTwP combat. It's the game that popularized if not created the RTwP RPG genre. To not have RTwP would be like getting the license to make a new Star Wars film and replacing the characters and lore with Star Trek characters and lore. RTwP was literally created for Baldur's Gate, and Baldur's Gate created RTwP. It'd be a betrayal of Baldur's Gate's legacy and a disrespect to its fans to have BG3 not be RTwP - and I'm sure Larian knows it. If they didn't want to make Baldur's Gate, including with the combat it is synonymous with... why would they have requested to make Baldur's Gate?
Also, I didn't know that about Larian's other games.
Read the interviews with Sven about making DOS1&2 turn based. The other games weren't turned based because publishers would allow them to, once they published their games, they were able to make them the way they wanted to, turn based. Plus they face less competition in turnbase.