Make it useless to even try. Don’t make it easy to detect when someone has burned through an ip - they’ll just pick the next up in the proxy list they bought. Make it so after 100 unsuccessful attempts, flag the ip and only allow it to log into accounts they’ve already logged into before (to stop them from using a real account to detect if they’ve been banned.) don’t say “you’ve been banned” - just shadowban the IP and always fail the auth. After a while they will notice but not after a ton of attempts