Hi,

Thanks for you question.

I didn't deploy yet Ionic/RN app to play store, and to be honest, not planning, but who knows what life will bring you :)

Regarding flutter it's easy especially if you setup CI/CD to work it for you. Manually, of course you can do it, just need to copy appropriate files (bundle/.apk, .ipa) to specific platform.

You can also visit this link for more information about debug/release. Also you can have different flavors/schemas

https://flutter.dev/docs/testing/build-modes#:~:text=The%20command%20flutter%20run%20%2D%2D,icon%20on%20the%20project%20page.

So flutter pain, I would say 5/10. (You need to know how to setup CI/CD)

Hope that someone can tell you more about doing the same thing on Ionic/RN frameworks.

Best,

Nihad