Last I heard Overwatch basically didn’t have lore. For the entirety of the lifespan of “Overwatch 1” (though overwatch 2 isn’t even actually a sequel) the timeline never advanced past the trailer cinematic from launch. All of the “lore” was just character backstory comics and backstory hints from their interactions in the spawn area of each match.
The gameplay really has nothing to do with the lore, but the lore never struck me as very optimistic. The premise of Overwatch is that once upon a time there was a team of superheroes who went around being superheroes and protecting people from the evil supervillains and stuff like that. But anyway, their superhero team collapsed and for a while it’s just been a shitty world where the supervillains do whatever they want. Now the superhero team is reforming with some new members. The end.
Idk how that could possibly be seen as optimistic personally lol