The only sure way is buying non-KYC so nothing is tying you to a Bitcoin purchase

Gov will always know when and how much Bitcoin you bought if you KYC even if you coinjoin

The only way to "undo" is selling the same amount back to the same exchange you bought from so it looks like you don't have any left. Then re-buying non-KYC. Don't have to do this all at once. You can do this slowly over time in chunks. You might lose a little bit to fees and taxes but the peace of mind going forward is worth it I think. Or you can roll the dice up to you.

Remember, the leeches in DC were discussing taxing unrealized gains a couple years ago.