Yeah collaborative custodians today can see all of your UTXOs, transactions, balances. And in theory they could even censor you (at gov request) or hold you to ransom in the event that you need their assistance to sign.

(btw with FROST we can run a service like unchained but completely private) https://lists.linuxfoundation.org/pipermail/bitcoin-dev/2023-August/021917.html