Ser, you cannot be more inaccurate in your post. Gambling companies are centralized entities that are regulated by another centralized governing entity. That itself makes it very impossible for a gambling company to be permissionless UNLESS it was built and implemented directly to use the Bitcoin blockchain, like DirectBet. But if you're demanding for BlackJack.Fun to be "permissionless", no, that can't be possible.
Yeah. Even instant withdrawal feature of casino still needs approval by the admin and some companies is just using a bot to automatically approved withdrawal with just some parameters like max/min withdrawal. But all this withdrawal will still undergo first to the casino admin before it will go out to the casino since casino balance is not on-chain and they are just using hot wallet balance to payout customer withdrawal.
Even games web3 still not permission less. I agree that directbet is the best example here for the real permission less game because it automatically payout on the sender address once the bet wins.
There is a decentralized gambling system in place at the DeFi world if you followed it during 2021, and even though that sounds weird, that was 2 years ago and it has been around for a while now. I am not saying that it's common, but there is this system where people are the bet provider, they put their money there and if gamblers lose then they make that profit, if gamblers win then they end up with some loss as well.
And in return, people gamble at a place that has a set house edge, and the deposit/withdrawal is on-chain hence it's not really that weird to have it instant. That's why it's possible but not very much preferred because it can be abused so much, centralized like this is much better because there is a team at the top securing it.