That sounds like writing and maintaining your own (cross-platform) version of Electron. And then not ending up with a native app for your troubles.
Not really. Just a shallow native layer that uses the platform as much as possible.
Except for the UI of course.
'Just'. Which platform? What are you going to render HTML with? And know it produces identical output, etc?
For example Webkit on Mac and iOS. Blink in Android and Chrome OS.
You'd need node for file system access though. Unless you write your own io layer
You could still use a web UI but without embedding Chrome and Node.