"Chaumian mints, also known as Chaumian banks, or blind mints, offer a compelling solution to these problems, particularly when operation is federated. Chaumian mints, through the use of blind signatures[0], have extremely appealing privacy properties. The mint operators do not know the number of users, their identities, account balances, or transaction histories. Additionally, mint transactions are cheap and can be performed at unlimited scale."

Blockstream just announced financially supporting MiniMint https://tftc.io/martys-bent/issue-1102-minimint-gets-support-from-blockstream/.

I don't know enough about blind mints yet but I wonder whether SN in its current form or other custodial wallet makers would be able to store user funds in blind mints. I need to research it more.