If you decouple your UI from your business logic, then you only have to re-write the UI. If you must use a web-based UI, then consider using the platforms native browser control rather than bundling electron.
Also Slack, Discord etc. are not really using React Native (but rather normal web react if they are not using another framework). You don't really need Chromium for React Native which significantly reduces memory footpring (in fact a react native app can be close to indistinguishable from a "normal" native app in most ways). You can probably reduce React Native overhead to not much more than 100-200MB compared to purely native apps which seems reasonable.
When I first started using react I loved it compared to what existed at the time, the ease of composing everything and the fact that it just used JS instead of a DSL for templating and it didn't mandate all these cargo-culted framework patterns.
But the warts are really starting to show up, writing React today with useEffect hooks everywhere reminds me of writing VHDL in college to simulate an automated train controller and now I'm reaching for things like XState to handle almost all state management (I have a feeling this complexity ends up appearing for all complex UI interactions though).
Also we are taking on a type system (which is good) but not seeing any of the performance benefits that could bring. Why is golang more than 100% faster than typescript? Both are statically typed languages but TS doesn't get any compiler optimizations because of the JS baggage.
That being said, I'll take JS with React + React Native if it means I can write apps once and ship to all three major platforms. It's exciting that ui frameworks like Tamagui allow for close to 90% code sharing.
When has there ever been a performant cross platform framework?
As a developer you will always have applications that are behind and have to wait on the third party.
This has been the case with every cross platform framework ever. See also JNI.
