sure
One of my best supports, Thresh, is extremely versatile which generally revolves around him easily being able to switch around being aggressive and passive. His hook, because of the delay, gives the opportunity to predict jukes once you get to high gold/low plat. This, in my opinion, turns into a game of rock paper scissors.
Say you shoot your hook predicting a juke to the left, and the enemy decides to juke straight. You miss
Say you shoot your hook predicting a juke to the right, and the enemy decides to juke right. You hit
Say you shoot your hook predicting a juke straight, and the enemy decides to juke right. You miss
When it turns into this scenario, it turns into luck. Sure, if I'm against a Thresh, I will try to mix around the way I juke but ultimately, it comes down to luck
another example would be Anivia. Playing as her, I see that she strugges earlygame and she lacks strong mobility. She is susceptible to ganks and relies on cooldowns. But i also know that a good Anivia knows to play passive until level 6, where you have a targettable 500 damage with your e-r combo, and to ward a sidebrush and stick to it.
finally, Morgana. Morgana is probably one of my most played mid laners and supports. I see how much she revolves around her cooldowns, her lack of mobility that is covered up with brute CC and how much she falls if she fails to hit her bread and butter Q. I also see how she can cover up missing her Q by initiating with ult, but getting close enough is difficult and many champions with strong dashes can easily leave her radius. Playing against her, dodging skillshots is not necessarily easy. It has a big radius, and you are bound to be hit by a 3 second snare every once in a while. Once you do, you're doomed to take a ton of damage if not your life.
In conclusion, I wouldn't necessarily say that you can instantly learn how to deal with a champion through playing the champion. It comes down to personal skill (csing, warding, map pressure, map awareness, game knowledge, roam)
To furthur analyze, I'll talk about a matchup i've played about a million times. Riven vs Renekton
Throughout most of laning phase, Riven will be scared, being denied of cs, and being punished heavily from Renekton. Renekton outdamges her at all parts of the game. Although, keep in mind that Riven has much more AoE and cooldowns that allows her to do more than renekton in teamfights. In this scenario, playing as renekton, I know that riven does more than me in teamfights. Does that help anything? not really
Playing as Riven, I know that renekton dominates me in every part of the game. Does that give me more damage? not at all
TL;DR
I bluntly disagree with you saying that " if you play AS a champ to the point you are comfortable with them, you can play AGAINST them with anyone"
There are some champions that you simplify can't play against, because their kit offers more than you can handle, or because they are plain op.
Yasuo vs Malz? Easily malz wins. Malz pushes yasuo into oblivion.
But wait! yasuo played malz a couple times before
that means that the push will stop and yasuo can win right?
no
yasuo will give up on lane
Morde vs Vayne top
Vayne will generally win. She will kite morde so he can't get his third q and if morde flashes for his third q, vayne will go invisible and outduel him
BUT WAIT
morde played vayne alot because he tryhards ranked
he now knows that theres nothing he can do and gives up on lane
I said that I wasn't sure about this post. I did NOT say it was completely wrong because yes, knowledge affects battle. But so does game knowledge, csing skills, and junglers. These things don't come from playing the champion that you think is op. These things come from practice
assuming this is blind. in ranked it comes down to counterpicking