>>535387695
You have a finite amount of stamina, anon. This game doesn't have an ELO system (and I have no idea why the 2.10 patch didn't add one to Master) but I'm going to talk about things as if it did: your rank is going to be based on how good your performance is as a player. If you want your rank to be high, only play when you're in a state where you can play your best. You become a worse player when you're tired, so your rank will change to reflect that.

Let's say you're in S+. You might be good enough to beat S++ players when you're refreshed and focused, but when you're tired you end up making more mistakes, playing more impulsively or failing to note your opponent's habits, and ending up playing around an S+ level. Your rank correctly reflects how you are when you're actively playing ranked in this case. If you want to rank up to S++, you would get there naturally just by only playing when you're in your best shape.

That doesn't mean you stop playing for the entire day when you start slipping: sometimes you only need to take a 5-10 minute break. I'd recommend doing that even after tough sets you win. If you're really struggling and can't get your head in the game, though, you should stop and do something else for a while, a few hours or even a day, before trying again. You can also swap to casual or lobby play where there are lower stakes.

Your performance in fighting games isn't just based on experience, knowledge and execution. Your mindset is extremely important, to the point that it's a legitimate strategy for one player to BM another and get them tilted in high stakes games. Avoid the tilt, take breaks when the tilt inevitably arrives. That's how you improve.