I wonder if the "most private" way to do this would be to distribute as a jupyter notebook or some sort of local bundle/distro to run as a local webapp?
But yeah, in terms of more standalone distribution and sandboxing, that's where the future desktop/mobile apps would be more appropriate. Of course, they'd be Electron-esque, but that would at least fulfill my end-goals of being privacy-first, offline-first, and providing 'long-term' software.