What's Up With Ranked Online? (All's Justice)

I don't know if there's crossplay or cheating or something else, and I'm not the best player, but every single match I've played in the past week has gone this way:

Round 1: I beat my opponent and usually have all three fighters left by the end

Rematch: I get utterly destroyed and don't even manage to take down one fighter

Maybe I've just gotten really unlucky with the matches I've played, but is there perhaps some kind of learning AI/software that cheaters are using, or even maybe just a ton of players hustling by losing intentionally and then devastating me in the second round?