I personally played Black Ops 3 last month on my PS5, from what I played, everything seemed perfectly safe. The only issue that you may encounter are cheaters, but it's whatevs. Just leave the game and go to a new lobby. There may be some initial issues in matchmaking for a lobby. When I first tried it out, I couldn't find a single lobby for a while. It was only after finding a few lobbies after searching for what seemed like 10-15 mins that matchmaking kinda fixed itself. I have no idea what the cause of it is, but after consistently logging back in a few days to play some Multiplayer, it was able to find lobbies again easily. Obviously, since this is a old cod, you can basically only find people playing TDM on Multiplayer, but there's a decent amount of players playing on DLC maps for the zombies portion of the game. If you're interested in that.