unskilled:/
i used to be a turbo-emo mongo tilter scout main several years ago. the best thing I ever did was to learn how to relax. I know that sounds like a super broad and unhelpful thing to say, but hear me out.
i personally had issues with worrying way too much about what other people thought about my personal ability, and how i was perceived as a player. this would make me just completely check out if i thought that i had already beefed enough that it didn't really matter what i did at that point because my statline and shit were gonna be god awful, and anybody who looked at the log would be like 'whos this trashcan,' and for whatever reason that upset me. I would also constantly compare myself to other players and their performance, and was just a super shitty mindset to have.
all i really had to do was to just relax; only worry about what's in front of me, and what i'm going to be doing. if i did something like miss a shot or get dumpstered by another player, i just had to brush it off and move on. if i made a misplay or something, i would try to remember to not do that, and then move on.
"just dont worry about it" sounds like the dumbest shit you can say to someone, but sometimes that's honestly the best thing you can do.
i can't be 100% on whats going on with you specifically, but i guarantee you that if, during matches, you stop worrying about how you 'always beef in matches,' and just play the game like you would in scrims, you will do 100% better. (and assuming you scrim capable teams that are comparable to the teams you play in matches, and you also do well in scrims, you definitely have the ability to play well in matches. it's all mental)