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.
Can't say never because some and most of all the reputable casinos that requires a d have our KYC are all newbies some day's and years back, and beside we can't say their will keep being the only reputable casinos that we will have to come across since the gambling market is an everly growing one with new casinos coming onboard that have better offers and can build their reputation and if you see such a casino you will know from their approach into the market, so one can give out such verification documents without fear.