There are probably better games for them to play together that scratch a lot of the same itches the average MMO would, but are more along the lines of single player with co-op. Monster Hunter is the obvious one, practically every manga that's referenced games in the past decade or so has referenced Monster Hunter at some point. Maya would probably love Genshin Impact, since she could whale the shit out of it with gacha rolls just to go PVE by herself or with Mameyama. Obviously not going to be referenced if it's not out when the manga was ongoing, though, so don't get me wrong on why I'm bringing it up. It's just too perfect a fit for Maya.