This is not okay

A tank's primary job in teamfights are to soak damage and provide utility to their team. Sure, they do damage, but that is definitely not their main objective

Obviously there are exceptions when you start looking at subclasses such as Vi, Mundo, Garen, and other diving Juggernaughts/Fighters that are meant to kill or at least create mayhem in the enemies backlines but that's why they aren't called tanks. When I say tanks, I mean Sion/Maokai/Braum/Sejuani who provide a lot of peel and cc for their team but not much damage.

And that brings me to the next topic: Champion Difficulty does not relate to damage output. Champion class does (and even "type" of damage output to), but not difficulty.

Sure, you can name champions like Azir or Lee Sin who are widely known as two of the more difficult champions in league but then I'd point out that Lee Sin's damage falls off around mid game and Azir's damage doesn't really get going until the mid game. Most ADC's do more damage Lee anyways, and nearly none of them are as difficult as Lee. Veigar should be a prime example of this, being one of the more easier champions he is widely known as the champion who is able to provide the most burst in the game.

"Easy" assassins like Fizz still do as much damage as more difficult assassins such as Zed. The only thing difficulty means is more options. It does not mean more damage