Does anyone happen to have an empty iOS app which only does the bluetooth connection/data transmission?

I just posted my semi-working code (no connection cleanup) in Swift (which I don't plan to finish):
https://github.com/baritonehands/TinyScreen_Smartwatch_iOS

I plan to finish this one in Ionic/JS:
https://github.com/baritonehands/TinyScreen_Smartwatch_Ionic

I created one trying to add a standard 22mm watch band.

NOTE: The button holes are too tall, and the band slots are too small. But you can tweak it to your liking.

https://www.tinkercad.com/things/bhkNObI4WTn-tinyscreen-smartwatch

I submitted a pull request for a fix to the Android app. Maybe my version will work for you?

https://github.com/baritonehands/TinyCircuits-TinyScreen-Android-App