Might be a bit of a hot take, or maybe not, I don't know but I kinda have trouble playing 2D Mario games nowadays. I'm not just talking about New Soup either, even SMB3 and SMW I don't have as much playing anymore. I just feel like levels just blend together since they usually share music and visual and music with other stages. Mario Bros Wonder is the only 2D Mario game I'm able to complete without getting completely bored. And that's a shame because 2D platformers are my favorite genre of games. That's kinda why I prefer Mega Man and Sonic games since every stage has different music, visuals and just feels unique. Does anyone feel the same way?
Eh, I wouldn't say they're boring, but the Mario platformers kinda got caught with two issues:
1. The New Super Mario Bros games are very unoriginal and uncreative, so the titles between Super Mario Land 2 and Super Mario Bros Wonder don't stand out much.
2. The original games have seen their ideas used by so many sequels that they don't seem original anymore. Super Mario Bros 3 is the Super Mario Bros game. It's the formula every New Super Mario Bros game is built on. So of course it feels a bit lacking now. It's been ripped off so much there's nothing left.
But the series can be fun and creative. Super Mario Bros 2 and the Super Mario Land games stand out a lot, as do the numerous fan games and mods based on the series with this gameplay style.