First of all, it's just a game. You don't get any real reward for winning. In game rewards don't count for anything, feel free to disagree, but skins won't improove your preformance, sorry.

The sole purpose is to have fun. If you aren't good enough to win, that's up to you not your mates. If you play with random players you have no right to get mad at them or tell them what to do or how to play. I get it, I really do. I get a lot of useless teammates on competitive and I get mad as well. But nevertheless you knew the risks of playing with randoms. Even I am bad sometimes, other times I carry. Personally it depends how I feel, if I'm in a good mood, I will likely play better, but if you trashtalk me cause I couldn't pull off 1v4 in the first or second round, of course my mood will drop and so will my preformance. Especially if you keep trashtalking players there is no way they will get any better.

Just let them be and if you are lucky they will relax and pick up the fight, I've seen a ton of K/D comebacks and had a ton of them myself.

Stop being toxic. Chill out and play. Have a nice day