There isn't really much evidence that this will be substantially better than Odyssey in terms of lifetime sales, other than historically 2d Mario games being bigger than 3d.
Odyssey sold 2m copies in 3 days on an install-base of 7m
Wonder sold 4.3m copies in 10 days on an install-base of 131m.
Odyssey had the lifetime sales advantage of now having 6 years of legs to work it's way up to 27m. Wonder has the launch sales advantage of a much higher install base.
Shipment numbers after the holiday quarter will give a pretty good indication on what's going on with this. But without a Switch 2 re-release of some kind I don't see this title breaking the 30m mark by much if at all. Mario games are heavily reliant on legs to reach such high sales and this is a game releasing basically a year before the console it is on is replaced, sure it should be BC but it's still gonna hurt it.
This isn't a New Horizons or BOTW moment for 2d Mario platformers.