I disagree, your aim is fine based on your Ana gameplay, up to a Master level. Now it might need to be cleaner if you wanted to hang in GM.
I think you’re a bit worse at these than you realize, I didn’t plan on listing these but I believe that these can help you improve your gameplay. Here’s some examples:
As Ana:
Reloading
1:00:24 - You reload too soon 3 times shortly after leaving your spawn. Your ammo count was 10/12 (first reload), this was fine because no one really needed healing at that moment, but you should be careful reloading so soon in case you need to use your healing right then. Your second reload was 11/12, and while you couldn’t see your Rein because you delayed yourself a bit by changing to Ana after the match had started, you could have been healing him if you were pushed up a little more there. The third reload is the worst one, you were 6/12 when you reloaded and your McCree could have used some healing.
Positioning
1:00:26 - Your positioning needs work here, you expose yourself after taking a fire-strike from the enemy Rein when you could be holding the corner and just healing your team.
Awareness/Target Prioritization
1:00:58 - You decide to take some meaningless shots at the enemy tanks and don’t realize that your Mercy needs healing since she’s burning to death. Keeping your other Support alive is usually the best way to give your team the best chance of winning.
1:02:19 - You could have immediately dipped to the right to try to help your Zarya but instead take a few meaningless shots at their Rein. Your Zarya dies here, if she was high charge and if you had the chance to save her, you could have helped your team out significantly.
Decision Making
1:01:57 - You peak the corner and try to DPS their Rein. This is a poor decision in general, you aren’t giving your team any value here and you get hit by the Sym right click but then you re-peak the corner and get killed by the enemy Rein’s fire-strike. This decision really hurts your team’s chances of taking this first point, making decisions to help preserve your life as Ana is the best way you can help your team win.
1:02:41 - You nano your Soldier 76 but then TURN around and head back towards spawn like you’re going to switch characters. This is a game losing decision right here, especially since your Soldier 76 gets some picks. You put yourself far behind the rest of your team and it would have been worse if you went all the way back and changed to a different healer, because your team would be without you for even longer. Changing characters is fine at the right time, but don’t do it when your team is trying to push. You shoot the enemy Bob even though it is meaningless and you really need to get to your team ASAP.
Anti-Nade Usage
1:03:05 - You miss your Zarya with the nade here which really hurts your chances of keeping her alive. Perhaps you were trying to hit both the enemy Rein and your Zarya? If so, it was close, but it’s better to preserve the life of your Zarya here and lead your nade in the direction your Zarya is moving (backwards) so that you can hit her. You then take shots at your Zarya and hit her with the 1st shot, 2nd shot, but miss the 3rd shot, then use a sleep dart. If you would have continued to heal her and land 2/3 of your shots, she may have survived.
Nano Boost Usage
1:01:27 - You get your first nano here.
1:02:41 - You use your nano here. It ends up being a solid nano because you combined it with your Soldier 76’s ultimate, but you did hold onto it for a while. Looking for opportunities to use the nano sooner will allow you to build more nanos for later, which can often give your team a higher chance of winning.
Useful Comms
1:03:25 - You are arguing with your Soldier 76, even though he’s literally the only one getting kills in the last 30 seconds, he’s doing all the work and killing all the targets he can, but it isn’t enough because you are hardly there to keep your team healed up.
As Zen:
1:03:53 - You discord the enemy Pharah and then your harmony goes away. You proceed to tunnel hard on the Pharah, not regarding your poor positioning, and end up dying without giving your team any heals and dealing little to no damage to the enemy Pharah. In a closer game, you would have just thrown the game for your team. You should have discorded her and then thrown a shot or two out, moved to cover, called her out for your team, etc.
I peaked in high Masters 3950 playing Zen and Ana, the mistakes you’re making in the first five minutes of your gameplay here are what is mostly holding you back, not your aim. I don’t see you climbing much in Diamond making these mistakes, it hurts your team too much. I see a lot of potential for you though, you could hit Masters if you clean up some of these mistakes. Cheers.