How would you meaningfully use this tool in offline mode?
What I meant was, you don't have to worry if the tool you're using suddenly disappears.
I tried React Native (only support JS on the client-side, need to build native modules to run some core functions for languages), Flutter (a few missing utilities, not so familiar).
I have answer why a desktop app in other comments so I won't repeat. Electron is the best fit in this situation.