I'd honestly want Larian to make DOS3 afterwards rather than BG4. I think with the new experience they can make their own IP a real banger.
I disagree. As good as DOS 1 and 2 were and as bad as some of these new weird D&D mechanics are I still think D&D is better. And BG3 is still close enough to 5e. Maybe if Larian were to create a whole new game type of their own that is a lot closer to D&D 5e maybe it might be as good but I don't know how close can they get without potential copyright problems. But I don't think there is going back without feeling like a massive leap backwards.
Their own IP does not need to appeal to the source material thats why they can express creativity more. There will be not much controversy and pressure from the outside like we have now with the new changes. I honestly want them to make a product of their own passion while not being tied by some external factors and conservative opinions. Stability kills creativity, as we've seen with a lot of Ubisoft titles for example. With DOS2 Larian proved that are willing to experiment by shaking the core mechanics of crowd control with the new armor system (which I find not at all perfect), as well as the origin. characters system and verticality.