I know a guy who apparently has hundreds of bitcoins looking to get into monero without raising attention to his old wallet! He's already converted several btc but he wants to exchange much more. I'm not really sure his best course of action...?
You can trade crypto-to-crypto on Bitfinex without kyc. Your friend will need to use a vpn if he's in the U.S. to make it look like he's not.
Cool. I'll suggest he look into it but if he can wait however long, atomic swap would be a nice option (!). But I have told him his old bitcoin should be nice and "untainted". He wants to buy something big with it, like a house, but not have it tracked back to his old wallet. It's not really my problem, lol, so I haven't researched it very hard.