I've tried building and running https://github.com/KhaosT/WatchActionButtonExample which works just fine.
In my own project however even with the StartWorkoutIntent implemented as per https://developer.apple.com/documentation/appintents/actionbuttonarticle the option for my app in the action button settings never appears, in the simulator or on a test device.
I've made sure WKBackgroundModes includes workout-processing and have fully implemented a StartWorkoutIntent (both a real implementation and also tried it with a dummy implementation from the KhaosT/WatchActionButtonExample repo). Despite all this I still can't get my app to appear in the action button settings screen.
Is there anything I can do to further debug this? Has anyone else run into a similar issue? I've just spent the entire day trying to make this work...