"Wtf I shit on Fizz in lane and he was 169 cs behind, but he oneshot me without counterplay"
I see this a lot but 1) thats what assassins do, especially Fizz as he has 0 ranged poke unlike any other assassin in the game. Doesnt matter that you are 4/0 when you built Morello and Ludens against him, "winning lane" doesnt make you tanky.
And 2) There is counterplay, his ult is a skillshot and he needs it to kill you. It also has 2 seconds delay before it does damage, his E and Q are possible to outplay/dodge too. Sure he can wait 2 seconds after hitting his ult and kill you "instantly" with a W proc, but he still has to land a high cooldown skillshot before doing it.
If thats a problem, you might as well say "Zed hit a double/triple Q on me and Death Mark is going to kill me, now there is no counterplay to him" lol.
and 4 afk's, then yea. Everyone.

try to build Sunfire/Triforce and just auto-attack.