Re: "un-KYC-ing" coins, if your reason for doing that is "I don't want to be in a database at a big company like Coinbase," I suspect it actually DOES help. If the coins you bought from Coinbase never move then they can confidently say you still have them. If you "un-KYC" them then you did move them and their database will have to reflect that your KYC'd addresses are empty now. That's not nothing. You might still be in the database, but now there's at least implicitly a question mark by the addresses they associate with you. They know they "once" had coins but any future reports they make about your holdings must reflect that all the addresses they know you had coins in are empty now.