Which stack allows you to be a web and mobile developer at the same time - electron.js, react?

Question

Mobile development

I heard about electron.js - there is no need to migrate from the world of java script, but you can immediately write a desktop application (for example, discord)
Now there are frameworks, platforms or APPROACHES that allow you to write a mobile site at the same time that looks like an application!
Give your vision!

Answer 1

Java\Kotlin.
You can write a backend for a webcam and native android.
There are no other reasonable options.

Answer 2

Full - only a few PLs (java, js)
Inadequate - js: react / react-native