What do you need to investigate? The bug that causes is - Yes investigate the diseases, please (the cheat exploit), but also treat the symptoms (permban cheaters)
In real-life police also puts people in investigative detention (permaban them now) and releases them when the evidence makes them innocent (unban when innocent).
JoeBiden and SuperHoang (or whatever he changed his profile name into this time) are without doubt cheaters.
We have stream footage of them cheating or at least their opponents experiencing TC deletion or Villagers idling without having them selected. They climb incredibly fast, win games in under a minute. https://aoenexus.com/profile/#6893982-3
It’s pretty pathetic how people are willing to do this. I’m not sure why people find it so enjoyable to smurf and hack the game. You aren’t actually playing it, so I don’t really see how it gives you any fun. It certainly isn’t pleasant for the other party, but they don’t seem to care. Removing family sharing on Steam, and implementing sanity checks is a really important step that should be taken. Don’t worry about balance for a while, or more DLCs. Just stop smurfing, Alt-f4, hacking, etc. Then fix a large number of other bugs and add regional or civ specific skins. THEN go back to balance and DLCs. Then advertise the game and try to grow the playerbase to help improve matchmaking.
Are you also the one who wrote the article on RedRocket? If yes, good job, that was a very interesting read. But please stop using this in public games. Most people already know that the game is not secure, at least those who play since Voobly know. The sanity check you suggest to implement would have no practical effect except wasting developer’s time, there would still be variants of the same exploit that can not be fixed like this (like your units auto-dodging projectiles), and there will still remain fundamentally unfixable exploits like map hacks.