Quinn should be flagged as an Assassin secondary Marksman, not a Marksman secondary Fighter

Fighters tend to deal sustained damage. Quinn is better at staying mobile and dealing short bursts of high damage (which is why she is poor at most bot lanes but works decently at top and against some mid lanes), hunting down targets, and Valor just deletes squishes from the map if they make mistakes.

She really isn't sustained ranged damage at all. Her damage potential is locked away in her E's cooldown and she offers minor utility that only helps with dueling. She doesn't have things in her kit that a marksman would like, but she does have amazing assassin mechanics.