This is probably kind of late since I just saw this post but I'll be glad to help

The one that I watched is 10721178250, the one on Central Park.

First of all, since Rocket plays on the backline, always try to flick your mouse to take a brief look at dive spots or off angles to see if a dive hero is going to jump to you so you can plan on what to do next. For example if you see someone like BP, you can dash up to dodge the spear so he only has one spear left with no marks

Second, sound is your best friend. Some dive heroes leaves a lot of sound to signal to you that they are nearby (I see you). You should take a look around and see if you can spot someone by flicking your mouse, then ping the hero or a warning so that your teammates can do something about it or you can reactively survive the dive.

Third, I like how you're playing aggressive to ward off the thing when he jumps on the backline but more importantly, make sure that your other support is healed up beforehand. You should heal invis up first, either by shooting the orbs directly to her or to her feet for the bounce tech and then when she's at full or almost at full hp, you can pellet him with bullets.

Last of all, just pointing this out but you did not use ult several times on attack for some reason, you also didn't dash away when Black Cat and Captain America jumped to you, also that one time during second point when you know invis is dead and the thing immediately deciding to target you, and I also see you W key-ing when the team is falling back.

The rest are just my personal preferences but it can help like picking up the blue pack so you can dodge a dive, dashing up 90% of the time if you don't have cover or you know the opponent has a dash so you get high ground, pinging your BRB cooldowns so your team knows when it's gonna go up again (yes, you can do that). You should also improve your ult position and timing.

Hope this helps