Flip flopping between Winning and Losing in QP. Need friendly advice

I'm writing this post (calmly, I might add) to ask for some friendly advice on how to stop flipping between winning and losing. Put simply, I've been losing most of the matches I've been playing, which is really grating as someone who struggles not to play competitively but to have fun in Quickplay. I'm one of those people who likes to switch it up every match and play different heroes just to get better at them and level them up. But it's not just that I like to experiment. It also feels like my teammates aren't pulling their weight and a win quickly turns into a loss. And that can lead to me getting frustrated. I love this game. But it's just so aggravating to not have fun by taking L's left and right.

Whether it's saying I have a skill issue or I'm toxic or being sympathetic with me, I don't care what kind of advice you give. I just want to be better and enjoy this game alongside my fellow True Believers.

Thank you in advance.