Decentralized casinos, which operate on blockchain technology, sometimes offer an alternative to traditional casinos by providing more anonymity and removing the need for KYC but obviously they are not entirely foolproof either. As with any online activity, there are inherent risks so using the reputate sites, checking in the forum... those are required.
Generally decentralized casinos do ask for KYC data. If the need arises such as for big withdrawal or if they are suspecting any un usual activities then they ask for KYC. You cannot guarantee that your data is secure in a reputed casino. Data leaks may happen and sometimes they might not delete your data after closure of your account. There is risk but if you are gambling you are always at a risk. I do not think KYC data can be such a big issue for a gambler.