I think the ideal way would be to either purchase crypto on P2P exchanges or other anonymous exchanges.
You can find some anonymous exchanges here:
https://livedarknet.com/anonymous-exchanges/
I do not give any guarantee for the safety of the links.
Anyway, how I purchase my cryptos is via a fake bank account + crypto exchange.
I simply charge my account and purchase my cryptos in the name of another person, once it's on the blockchain I am safe!
I could help with the accounts..