The ultimate solution is to allow for P2P online with official servers as the default, and just warn people that you might encounter cheaters if you use P2P. Can even go a step further and separate the player pools between unmodded and modded clients. So you can play online with mods, but run the risk of encountering cheaters. P2P should mean you can ban certain people from invading you due to hacks or high ping similar to DSOM back in the day