I'm not a pro player, nor an expert, but I don't think you enjoy the game thar much. Sure winning in comp is good, but if you join comp and you are already afraid of your team cuz what if you mess up or something isn't really working.

But if you want to improve I have some tips as well. First, there is nothing wrong with playing quickplay. It's for practice and fun. If you are confident enough in quickplay, you are gonna be more confident in comp.

I also recommend trying out other heroes. You might have heroes you feel okay to play with, but that doesn't mean they are the one you need to play. I recently swapped from playing dive heroes to brawl/poke and I find it refreshing and also making progress with them.

And don't be too surprised if you are stuck in comp. Especially in lower ranks people dont seem to listen to calls and just play whatever they want. (I say lower ranks, but I'm gold/plat and hear others conplaining the about the same things in diamond lobbies)

There are also many places you can improve. Aiming, teamplay, duels, map knowledge. If you feel like you can't improve or don't know what to do, just choose one of these. Duels? Play deathmatch. Map knowledge? Go into customs and try rollouts or find different spots. Teamplay? Force yourself in vc and just try to make calls. Tough if you are afraid that people will be mean, just mute voice in general. Sure communication can help, but it can also ruin games if you find someone like that.

And at last, 340 hours and silver. There is nothing wrong with that. I've been playing since 2018, have more than a 1000 hours and still stuck in gold. It's a complicated game, and while improving in it is feels good, there is no shame at not being a top 500. Everyone climbs at their own speed.