Adding XMR into the mix adds exchange rate risk. The longer you hold it, the bigger the exchange rate risk. You also have to be careful when you swap back to BTC to use different addresses and different amounts than you used when swapping from BTC to XMR (and to not use a wallet that shares your addresses with a third party, or they could link your addresses together). If you accept these risks and manage them well then what you suggest may be an effective way to de-link your spending wallet from your KYC vendor. Though, if you are willing to take on the exchange rate risk of an altcoin you may as well use state of the art privacy technology i.e. shielded transactions -- as implemented in Zcash and its forks, Railgun, and quite a few other projects, DYOR. Monero's RingCT is outdated at this point. See: https://yewtu.be/watch?v=9s3EbSKDA3o