Sticker Star is nortoriously one of the worst Paper Mario games. lol
I would start with Thousand Year Door (if you can figure out a way to play it) or the N64 game.
I am going to start with the one that's available on NSO. And if they don't release any remake (or NSO version) of any other Paper Mario, will get the one they released on Switch (Origami King?). I have heard a lot about Thousand Year Door, hope they release it on NSO.