Essentially, it comes down to two points:

- Your non-KYC UTXOs combined with KYC ones become KYC UTXOs.

- Do you mind the future traceability of these UTXOs?

If yes:

Mix them three or more times and transfer to cold storage. This breaks the link to your identity for subsequent transactions.

If no:

Directly place your UTXOs into cold storage without mixing.

Regarding UTXO size, you already have my recommendation from earlier today.