Just a maybe too much specific rant about current balance

So, I'm not one of those who rant every season every time something changes, I usually tend to just adapt. With that said, there is something that really gets on my nerves and actually has somewhat specific conditions. These are:

1. You are lowish elo, you often play in a 5-men premade with friends of similar elo.
2. You only play normals.
3. You often switch roles and/or take champions you don't really play, because it's been a while since you last played them or simply because you are not comfortable in that role and you don't usually play it.

In the last two seasons, I still have to win a game with these conditions. Or rather, I still have to have fun in a game with these conditions. The point is not really win, but it's rather "doing your thing" with the champ you chose. Until three years go, you could go, if you wanted, things like Hecarim full Mspeed for the juicy one-shots. Maybe you lost, but you managed to reach that point and to do even one one-shot, and it was worth it. Now you really can't. The problem is not the macro play, but actually the micro and the mechanics on your champ. When talking about current balance, it's righfully assumed that you know well your champion because, to be fair, LoL is not really a hard game from a mechanical standpoint, with maybe some harder champions that need a bit of training like Riven, Zed or Lee Sin. But it's not like I'm playing champions for the first time. I've played them before, I know their kits, I know their playstyle, I just don't know their numbers, power spikes and optimal builds. Which, again, shouldn't be that impactful in a normal game where you don't play to win, but rather to actually play. But now if you do something like this and end up slightly behind (as expected, and again, shouldn't be a problem) you now either get bursted if you are squishy or melted if you are tanky. And you can't really shake off the thought that you got cheesed out by a power spike that you couldn't know and that shouldn't give that much advantage. Like when you are Lucian and Leona vs Jhin and Thresh, then at some point Thresh randomly decides to come directly at you when for the last 5 minutes they have been zoned out from farm, randomly pulls out damage that he didn't have before and kills you, with Jhin only hitting you once because Leona stunned him as soon as Thresh engaged on you, but it didn't matter, cause Thresh took 90% of your health with a combo. You can't shake off the feeling that you just can't play a champion just because you want to play him for fun anymore, because when you start losing it just becomes a stomp. You can't shake off the feeling that you now need to know the power spikes of every champion in the game beforehand or you risk getting cheesed pre-6. So, just a maybe too much specific rant about current balance.