Just looking at previous sales (according to the numbers on this site).
KH 6.4m
KH2 4.3m
GoW 4.5m
GoW2 4.1m
GoW3 4.8m
The first Kingdom Hearts was the most popular, but they are roughly in the same ballpark on the other games. I think I've got to give it to KH3, but it would be pretty close.
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