Does OW2 even run on the SteamDeck? Checking ProtonDB says it's unknown compatibility, but generally competitive PvP games struggle due to their highly intrusive DRM/anti-cheat that wants root kit level access.
Funnily enough there have been a few times that Wine specific problems have been addressed by the BNet team (pre steamdeck) and when Linux players were accidentally banned they have unbanned them iirc in some scenarios.