weaknesses will always remain. And players who try to exploit this will always stay, you can't do much about that. You can draw up a policy policy, and in combination with a kyc policy you can put a limit on a certain player, for example. That way it becomes much less interesting for a player to continue cheating.
There's always an issue on any gambling site, just like my experience before about my withdrawals considering that they are the top betting site and yet they are far from being perfect which I think none on any site claimed to be perfect. Vulnerabilities are always there since hackers are really great as well, imagine Binance got expose to those hackers, what more the other site especially in gambling where security is the main concern.
What kind of issue you encounter on your withdrawal because most the gambling don't have vulnerabilities in regards with this matter due to there tight security. Some of the Casino requires KYC if you will withdraw an amount above the minimum threshold for non-KYC account. Most of the vulnerabilities of casino nowadays are from there software provider like slots and live casino since Casino are now just using 3rd party game provider on there games. Only few of them have original games so the problem always occur on 3rd party software.