I’ve been trying to find a way to keep my bitcoin in a multisig wallet, currently on sparrow and have trusted family members in distant locations perform signing of various keys for me. I’ve been using a blockstream jade signer and 21×21 qr codes of a seed phrase. I can save a file to disc of my psbt, and securely send that file to my collaborator to sign. It works fine if I provide the entire wallet descriptor file and my signer duplicates my entire sparrow multisig wallet, but when I do that they see all the transactions and the bitcoin balance.
Nunchuk finney wallet has something they call “blind co-signer” described at which is pretty much what I am looking for. Except Sparrow seems to be better supported and more widely used than nunchuk.
I asked Google “how to keep xpub and path information private from collaborating signers of my multisig wallet” and received some information that sounded hopeful but appeared to be unsourced. Maybe it was an AI hallucination?