Yeah mercy’s big flaw is she requires good dps essentially which in lower ranks if you don’t bring a Smurf along is hit or miss.
You’d be far better generally with a dos support when you get stuck with 2 brain cell Tommy. But when you bring the end is now soujorn Bobby then yeah she looks like a gosh darn busted hero. That’s so rare though in solo queue though.
People just run into a Smurf or two a night and go well that’s an absolute busted.
Meanwhile I get the mercy running with a sombra venture basically doing nothing as they have no hitscan to support and the tanks doomfist so you know they might as well just not even be in the game.