Surprised people are saying under 24 million. It'll probably be at like 19.5 million by end of this year, and should have at least 3 more years to sell before Switch is even replaced. No way is it gonna start suddenly selling only a million copies a year just a few months from now. Even if it only did a million a year, then let's say another 500k total from 2024 onward, that'd still put it at 23 million and like I just said, no way sales suddenly drop off that much just a few months from now. Plus late in Switch's life it should be put down to $30 which will help. It should do 24 million at minimum, with 26+ million being a high mark.

3D Mario collection plus the next 3D Mario will lower it’s leg

I think it'll end up within the 26.0-27.9 million range. Just short of 30 million

BQ: I think Nintendo will be content with doing that rumored 3D All Stars collection (I believe it's true), and it'll have the Switch be THE system to get all the 3D Mario games. And they'll save the next 3D Mario game for Switch 2, possibly even as a launch title. As for what that game will be, words can't describe how BADLY I want a Galaxy 3!

I'd say 23-25 million.

As for the bonus question, I'm not sure, given Odyssey's sales, a sequel to it seems like a safe bet, but Nintendo is really unpredictable in this aspect.