Check out other Assassin’s Creed games! I agree that Red Dead Redemption is anther good suggestion. I suggest the first one as well. Maybe Fable? The second one was my favorite, but people rave about the first one as well. I didn’t play the first one until I didn’t have as much time to game.
This might be a miss, but the Sims can be insane with mods. You can cheat their needs and not worry about those. Sims 3 is open world and the best of the series, but I’m not as familiar with the mods available for it. There are Sims 4 mods that introduce murder (guns and knives provided of course), drugs and gangs, zombies, prostitution, murderous toddlers, and much more that I can’t think of right now.
Modders are fucking lunatics when it comes to the Sims. Someone made a mod for Sims 3 where you could grill and eat a baby. EA stepped in to shut that down…