I bet this is a falling out with Hasbro execs on royalties. BG3 royalties were a cash cow this year for Hasbro, pushing Wizards (as a division) to be quite profitable, while almost all other divisions in their company lost money.
So now the agreement is over, and Larian is like: we will own the IP on our next project instead of paying $90M to Hasbro... And fair enough -- they've shown they can kick ass. Hasbro is probably gambling that it's the IP that made the money, and not Larian being magic in a bottle as a developer. So they'll kick tires on selling BG4 to another studio.
BG3 will go down in history as the legendary game before enshittification. Larian will make a few great games that don't sell as well -- before selling out to a whale that dumps money on the owner's front lawn (see also BioWare). The devs who made BG3 will found indie studios and make cool shit for a decade or two. So the wheel turns.