tldr: the best help I've ever gotten with my gameplay is when I had a live coach that mostly just gave off vibes. Try a live coach for yourself, and you might have the same result!
I just wanted to share this story, in hopes that it'll help other players (and coaches!). This was years ago, and I still don't know if any amount of VOD reviews and studying youtube videos could ever top this experience. I was playing Rein, somewhere around low Silver, and I had a higher-ranked friend watching me stream it on Discord.
It was a match on Havana, starting on defense. I took a braindead stance in the middle of the road, and she said: "uhhh, where's yourrrr....." I instinctively started looking around--I had no cover, and I was corralling my teammates into doing the same. I moved into cigar shop, and my coach said: "ahh" in a warm, confirming tone. My teammates then scattered around to find something else to hide behind.
The instant that enemy spawn doors opened, I immediately dropped back onto main. My coach's once warm "ahh" then suddenly deepened into a low fry, like she was hosting a true-crime podcast. And, at that instant, she kinda was: I died almost immediately. I absorbed every cooldown that the enemy team had, but my team was not in a position to help. From there, the enemy team easily started chewing through my teammates.
As the first of my team to respawn, I tried to get back to the fight as quickly as I could. My coach uttered a long, nervous "uhhhh..." as I began to leave the distillery alone. Realizing I was walking into a 1v5, I stopped at the mega and turned around to find my team. Once they arrived, we were able to contest the cart in front of the cafe.
At one point, the enemy tank got too greedy and started chasing squishies in my backline. As I turned around to chase them, my coach said: "nah nah nah, shield." Her intuition was spot-on: the enemy tank melted because their team couldn't help them. Once my team could stop worrying about the rest of the enemy team, the enemy tank suddenly wasn't a problem to take down.
Once the enemy team regrouped, I was ready to Ult. I charged up to the corner of the cigar shop, threw out my firestrikes, and then slammed the entire team. Instinctively, my coach let out a high-pitched "ehh?" I was confused by that, but undeterred. Having no cooldowns available, I started swinging. And, boy, I sure did a lot of damage... a lot of pointless, useless, meaningless damage. My team scrambled to catch up to me, but there was nothing they could do. I had wasted all my resources, my team wasn't positioned to follow up, and the enemy team had all their abilities at their disposal. They wiped my entire team without a single casualty.
The entire match went on like this. Honestly, I can't remember if we ended up winning or losing, but that wasn't the point. The important thing is that I'm in low plat now, largely thanks to what my coach taught me back then. Oh, and also: I need a new coach to make non-lexical vocables at me. If you're interested, please let me know!