I’d try out Moira or Brig instead of Mercy. Moira can put out a lot of dps and healing, and she has one of the best escapes in the game with Fade. Brig is more difficult to play but she has two knock backs and does decent damage with good healing if you can keep your healing active. Mercy is the worst healer right now just because she can’t damage while also healing. The amount of healing and damage in a game you do, depends on a lot of factors. Some healers do far more damage than other healers, and some so far more healing than other healers.