Take 3-6 month rest?
My bills are due every month, no rest for the wicked.
Ill guarantee (I've said this before on another thread) they have had a team, already working on the next project, weather it be a think tank, lawyers or what ever. You must always have something brewing or every one will be homeless.
My expectation is that they have multiple small teams looking at different options right now. They're going to be at least roughing out something with their own IP in case there is nothing further going on with BG3. There's also going to be a team looking into moving further with BG3 whether it's expansions or a sequel unless the agreement with WoTC explicitly forbids that (and it may require that they look into further BG3 related work if certain thresholds are met). They may even be looking at making a game based on yet another IP...
We don't know exactly what they are doing, but you're right that we can be sure they are doing something.
