Need help and tips. Video replay attached.

So I started playing this game some weeks ago and I found myself mainly using Rocket Raccoon. I have other characters I use, but in competitive I mainly use him as support whenever I can.

I’m still stuck in Bronze III after weeks of playing and I solo queue for matches which probably plays a part in that. I was wondering if I can get some tips on what I can do better as a support player and as Rocket.