I think we might also not fully understand how BG3 happened. It is a massive step up ambition wise from D:OS2, and I suspect there is more at play here than Larian using success of D:OS2 for their next project.
Larian got a lot of funding from various sources. They sold 30% of their shares to Tencent, they made a juicy partnership with Stadia, they most likely have a lot of help from WotC who want to show their license in the best light, they got help from Microsoft employee for they console port, and of course there is all the orders from early access at 60$ the unit (more than pretty much any games nowadays).
