Most gambling sites now require KYC upfront and on the latter part. The gambling world is becoming more and more centralized. I don't know if it's a positive thing or not. But I guess it will depend on how we will view it according to our situation.
I think most gamblers only focus on the convenience and security of the gambling platform and the reputation of the casino from the community's assessment, I do not exclude KYC requests but almost all the top casinos have added KYC to the terms and conditions. In another case, the user has lost his mobile and he has lost access to all data and gambling accounts stored on the mobile, he cannot recover the gambling account and the casino platform team also cannot recover the user's account ownership without saving the KYC of the previous main user, so KYC is not too bad for proof of account ownership but only for trusted and top reputed casinos.