I think unless the game is within the last few years or has a good playerbase, it will be hard playing online.
Not sure on modern day fighting games if you will play online. Maybe Mortal Kombat 11, or whichever is the latest as that could have players, latest Street Fighter maybe. I play ROMs for retro fighting games lately.
Yeah sounds a bit like all call of duty predecessors, most online gamers move to the newest one and the old ones are either empty or full of hackers.
Cool, will check one out, cheers!