You have a closed source rootkit designed for finding data in raw memory (like passwords from an unlocked password manager), loaded into many gamer's machines, which many software engineers are. Some anti cheat explicitly support's arbitrary remote code execution by design. Many people mix their personal password vaults with their company's, which means that if you successfully hack an anticheat company and you can read the raw memory of an opened password manager with a program that is already designed to scan all processes memory, you now potentially have extremely valuable credentials. A small portion will even do things like add their 2fac keys into their vaults.
Here is Gabe Newell's thoughts on AntiCheat that are very relevant to this thread: https://www.reddit.com/r/gaming/comments/1y70ej/valve_vac_an...
Of course the other problem is the 23andMe problem and enshitification. Even if the data uploaded by anti-cheat isn't used right now, the storage of data alone creates incentive for abuse.