I Think I'm Just Trash At This Game

I don't think I deserve to be Diamond. I think I'm garbage.
I'm pretty sure the ease of Rocket Raccoon carried me all the way here and I'm honestly a Bronze 1 player at the very best. I don't think I earned any of those wins, and now that I'm in Diamond I'm almost exclusively losing. My winrate has plummeted and I've dropped to Plat 1 two times now, and I'm dropping back down there again now.

I can't play any of the "good" characters because my aim is horrific. I'm 30 and I have some kind of arthritis in my hands, my reaction time isn't good anymore and I'm honestly stupid.

A lot of people have told me that climbing in this game is extremely easy and people that are garbage are at much higher ranks than they should be, because of both the chrono shield and you getting more points for winning than losing, and honestly I think maybe they're right.
I played Overwatch for years and years and years and I was hard stuck in Silver for RQ and Gold for OQ. Could never climb out no matter what.

I kept fooling myself in Rivals that I'm good enough to be GM, that it's my teammates not me, that if I just had teammates that coordinated I could climb there, but I think it's dawned on me that it's me. I'm trash, I'm awful, I'm terrible at this game, and I will NEVER be GM, no matter how hard I try or what I do, it's literally impossible because I am GARBAGE.
It took me till around level 38 to reach Diamond. That's awful.

Take a look at this: 10827631376
Lost, because of me. I'm stupid and I only know how to play Rocket, if I swapped off we would have won but I only really know how to play Rocket so I just made my whole team lose.
Here's another one: 10114432157
You can clearly see I have NO IDEA what I'm doing. Forget that I don't know the map, I have no clue what to do or when to do it and I mess up basic skills many many times and lose the match for my team.

I also constantly get flamed by my own teammates. Constantly. I had two recent matches where several people called me trash.

I guarantee you 100% that if I stopped playing Rocket and started only playing someone like Mantis, I would drop all the way down to Bronze 3 in record time.

I can only really play Rocket because he's the easiest character in the game and takes almost zero skill, of which I have none.
I have almost all of Rocket's skins and I can't even enjoy him anymore because now I know him being the easiest and stupidest character is what made me think I'm good and I'm not. I don't even want to pick him anymore.

I think I'm done, this game is just making me feel bad now and making me realize that I am terrible at video games and always will be, there's no point. Nobody I know plays this or will play it with me, and the few friends that do are in ranks like Celestial which just makes me feel even worse and I don't even want to talk to them anymore because they make me feel even more inferior than I already do.

I know nobody cares but whatever. I'll probably get nothing but insulting replies like I always do in this and every sub and honestly I deserve it.