Well, Almost all the online casinos nowadays is support USDT deposits and withdrawals some of them only support ethereum and Tron network but I believe there is an online casino that accepts usdt at most cheapest fees like Layer 2 Chain, especially dApp gambling site that has a smart contract in it.

About the KYC well some casino usually let you deposit without kyc and dont ask KYC till you hit big win hahahah. But you do need to read their Terms of service first before make any deposit just in case you know