Scammers frequently use Discord. It's a popular distribution point for game-hype-cycle scams, and GTA 6 attracts plenty.
Common patterns
Servers offering 'leaked builds'. DMs from accounts saying they have access. Phishing-style invites trying to get your account credentials. Crypto-flavoured 'NFT GTA 6' offers. None of these are officially related to GTA 6 in any way.
How to handle
View unsolicited DMs as suspicious. Avoid clicking links from unknown servers. Avoid sharing account credentials. Report suspicious activity to Discord trust-and-safety when appropriate.