@OP you better off to understand and play with demo account of every games, so you can learn by practice. Theory isn't enough to make you understand.
Unfortunately, you can forget about privacy and personal data protection in the twenty-first century. Major brands or websites say that they have the best security protection installed, which will not allow hackers to break into the system. However, people are already aware of several dozen cases of database draining.
Then you should learn how to secure your privacy, you can start by a little thing to not publish your daily routine and hide all of your personal pictures on any social medias. It's hard to achieve fully anonymous privacy, but it doesn't mean impossible.
I just think it's impossible now. Because almost all people who use the Internet have such a legacy on the network that it will simply not be possible to maintain 100% anonymity. I think VPN does not help because it simply allows in some cases to bypass the blocking of individual sites.
But harm from KYC certainly takes place because it is the voluntary provision of information about yourself to a specific organization or even a person. And then he can dispose of this data as he wants. Although, of course, they all always write that personal data is strictly confidential and is not disclosed to unauthorized persons. You have to be very naive to believe this.