Wait what do i do against tank comps as mid exactly???

So half of you are tankier than me, you outscale me in teamfights whether or not you lose lane... and you're going to outscale me naturally too... what???? Like even some mid laners build tanky and somehow manage to still deal decent damage. I actually don't understand... is there an anti tank mid laner or do i just play/learn vayne mid and pray??

My mid library is cassiopiea,zoe, vlad, lux, and fizz in certain matchups. I can PLAY other champions those are just the ones I'd consider myself good for my rank with.

Last game as an example had Ryze, Galio, Olaf, and Ornn ( im so sick of seeing him every 3 games). I was playing zoe. I think you can imagine how me trying to do my job went.