I think bot revives don't count, but may have counted at one time and then stopped being counted or maybe even were subtracted.
I think it only counts if you do a revive, as a support player, in multiplayer, and not in gauntlet or battle royale. And, like I said, I think only real humans count at the moment; or, at least, defintely, only in verified-mode servers with full XP and maybe or maybe not at all in casual breakthrough.
I got my 1996 revive achievement after 2100 something total counted revives (including with other classes). Custom Portal has no progression, so none if that was counted either way, so it seems almost everything else I played in real games counted.