Trezor Sicherheitsfrage

There’s nothing inherently linking the individual addresses in your wallet. That is: given one address, no one can calculate another address. But your behavior could provide clues that may compromise that privacy. As a very simple example, if you make two 1 BTC deposits to two separate addresses and then make a single 2 BTC transfer out, then those two addresses are “linked”. So even though you only told Coinbase about one of the addresses, say, if they wanted to they could sleuth out the link to the other one. Also, anyone you share your XPUB with will have visibility into ALL the addresses.

ETA: if you just want to keep your post-mix coins separate from your non-mixed coins, a new account on Trezor is a fine way to do that. So tell Coinbase about addresses in Trezor Account A. Withdraw from there to your coinjoin implementation. After mixing, move coins to Trezor Account B.

> I would like to break the chain that links my kyc purchase to my hardware wallet, most likely via coinbase -> coin join -> hardware wallet, but need to know if I first need to wipe my hardware wallet (after moving funds of course).

Yes, this is the way. Though a few things to think about. If you put your „clean“ coins on the same HW wallet account as your „dirty“ coins, your wallet won’t know the difference and might inadvertently link them in future transactions. You want to keep clean / dirty on either different accounts in the same wallet, or on different wallets (aka passphrase) on the same trezor.

Also, withdrawing directly into a coinjoin may be ill advised as well.