You won't like it, but basically, KYC/AML everyone. Valid ID, Voter's style registration, Passports, Driver's License, Social Security Numbers (no one is supposed to give these out, but they do anyway)

But even with that, you'll have fake IDs and dead people claiming their airdrops. You'll have entire armies from world war 2 wanting their "fair share". Exchanges can't stop this now. Banks can't stop it. Even national elections can't stop it.

So, good luck. You can try to do a good job, but some will get through. I'm trying to do a country coin myself, my requirement would be birth certificates or some other valid national id, and maybe a police certificate. But every high ranking corrupt criminal politician has all of those anyway. You'll just have to accept that exploits are there. Technical exploits. Social exploits. Smart people. Dumb people.