It’s actually completely normal. Using their site and making withdrawals is fine, but since they have verification levels, if your account doesn’t have KYC yet, of course there will be limitations on what you can do and how much you can withdraw. Asking for KYC isn’t a big deal nowadays, and you don’t have to worry as long as the site is legit, you’ll get your winnings once it’s completed, I don’t see any problem with that.
It is true that you said with a statement about the KYC, after all, It is true that you said with a statement about the KYC, after all, the purpose of this KYC is for our own safety and comfort in terms of gambling precisely withdrawal. Although this is proposed by the casino when we are going to make a big withdrawal, we have to finish it, than the victory cannot be withdrawn so it is better to follow the direction of the casin, especially if the Casino has good reutation then don't hesitate to finish it.