VGC has Sun/Moon at 15.17m and Ultra Sun/Moon at 7.15. That total is 22.32m. To me that is the ceiling for Sword/Shield. I think it will do close to that but not more. That actually puts it just below Gold/Silver, but above all of the other games (except the original).
curl-6 bet me that PS5 + X|S sales would reach 56m before year end 2023 and he was right.
My Bet With curl-6
My Threads:
Master Thread, Game of the Year/Decade
Switch Will Be #1 All Time
Zelda Will Outsell Mario (Achieved)
How Much Will MH Rise sell?
My Bet With Metallox