Looks like the S2 version of the older games is just the normal S1 game with a code for the upgrade. So there's no reason to buy the Switch 2 versions of games at all unless you never bought it before.
Discussion
You're paying for the game plus upgrade patch~ :'D
I quit buyin Nintendo games a while back. They’re too stingy to cut prices on old titles unless it’s some rare sale. Mario Kart and their other IPs? Rather dated and recycled gameplay.. The Palworld mess didn’t help their case either. I used to like with Nintendo, but now it’s just another childhood memory hijacked by corpo greed.