Overwatch 2’s average Steam player count has dropped 39% since Marvel Rivals was released
However, Marvel Rivals was then released on December 5, and according to Steam DB the average Overwatch 2 player count for December was 25,248, a drop of 21.7%. SteamDB also notes that in the past 30 days (i.e. January to date), the average has been 19,745, a further 21.8% drop.