No KYC doesn't mean it's decentralised, so centralisation and KYC is completely different for now almost every trusted crypto casino is centralised so they are operating under a regulatory body and the site has to follow the guidelines of regulatory body as of now almost every regulatory body implemented KYC as mandatory to tackle money laundering by scammer which is the sole reason why we can't see a casino without KYC.
I highly agree with you, KYC and decentralization are two different thing. Decentralized gambling platform mostly focus only on simple games such as dice, crash, It is obvious that casino that has lots of games to offer is centralized. I haven't known any casino that has lots of game provider to be decentralized. About KYC, I believe this is required by gambling regulatory board and mostly implemented by licensed casino since they have to follow the regulation. And also one way of the casino to verify the users if suspicious activity is detected on the account.
If you're too concern about kyc and don't want to end up playing in casinos implementing it then you really have to read their TOS and understand every details to become aware of their rules. As you've said, we have an option to look for casinos who are not restrict about kyc wherein you can play without worrying about it.
However nowadays if the casino is regulated and licensed it is likely that they will ask you to comply for this requirement especially if you're a whale gambler or you happen to win huge amount.
I think there isn't any single casino that won't ever ask it at all. There are some casinos like roobet which asks a few simple stuff even beforehand, and there are a few places that will ask everything beforehand, but even the casinos that doesn't ask anything at all upfront, may end up asking for it when it comes to something suspicious.
If any casino feels like you are a shady gambler and there is something wrong with your account, they will ask your KYC and that is going to end up with some trouble for you. There isn't a single one that will ask absolutely nothing, that just doesn't exists, all of them will ask if they feel like they need to ask it.
there are still some casino that do not ask KYC unless a huge amount of money is involve or some suspicious or abnormal activity is detected.