I don’t like this part because you will not have a chance to back down on a casino if you happened to realize late that the casino is bad while you already submitted your KYC.
To be on the safe side, I would never submit my KYC to any new casino. So if the new casino doesn't allow you to play or test their casino without KYC, I will just ignore that casino. Yes, KYC submission is a must on most of the gambling sites but i will rather stick to those sites which are running for years and gambler's KYC is considered safe on those site. Yes, the risks are everywhere as we never know if any site get hacks anytime and our KYC data is stolen but no one has control over these unexpected events.