[nejsjsjsbsb]

This cross my mind too (as a why hasn't this been built?).

For now I think a few meh options:

You let the customer BYO encryption keys. You need tech savvy customers.

You offer to install on customers cloud. Also tech savvy.

For some solutions, a web front end that talks to Dropbox etc. may suffice. You just serve up static HTML.

Desktop app.

Web app with download/upload like Exaclidraw.

[alliewithane]

The main problem is that I need to process their private data frequently. This means end-to-end encryption is not really an option.