Have you considered Cashu?

- Doesn’t require KYC

- Users can select their preferred custodian (removes liability from Primal if custodian is down)

- Provides Lightning and ecash capabilities (nutzaps/new features become possible)

- You can run your own npubx.cash server for providing Lightning addresses

- User’s balance and transactions (outside of public zap/nutzap events) are private

Here’s a quick demo to show how easy it could be to implement:

https://blossom.primal.net/74091e70adbc2d975f8cb297ea4af5f83e418853a5424af5b5898a9e110079da.mp4