1) use BTC mixer such as WASABI
But there are talks about people getting involved in illegal things just because their BTC were mixed with illegal related BTC.
Wasabi is Bitcoin wallet with built-in CoinJoin, not mixer.
2) send your BTC to an exchange like bitbox, kucoin, huobi ... then buy monero, send them to another exchange like bitbox, kucoin, huobi ... and buy back BTC
But what if those exchange are linked together so that monero transaction between two of them will be identified.
It's likely they will ask you KYC verification and write all transaction details. If government decide to track you, you'll be tracked easily.