Possibly a solution to this is set up an email account verification system ...

I think that self-sovereign identity (SSI) blockchains will ultimately be the solution to this.

"These solutions use cryptography, zero-knowledge proofs, and blockchain elements to create systems of identification that can be cryptographically proven without the need for centralised certification."
https://www.forbes.com/sites/alastairjohnson/2021/11/15/beyond-the-device-with-self-sovereign-identities/

I think that this would allow people to demonstrate that they are individuals whilst at the same time revealing no personal data about themselves to the game owner. Or something! I need to read up on it more. zk proofs always confuse me.

Cheqd is doing this on Cosmos and I know I've seen similar ideas in other ecosystems.