Other methods are:

on-chain > lightning > ecash > lightning > on-chain (would want to do this in batches though)

Use Jam Joinmarket (but you would need to run your own server, such as an Umbrel)

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There are also considerations around using a public vs. private node.

This all achieves future anonymity but doesn't erase the KYC trail. And you would want to move the btc in batches rather than a massive lump sum. Also, the final destination wallet should be oe that has not had any connection to KYC bitcoin.