Thanks for posting about this. At the present time, Apple has not opened up the action button to external Apps, so it's not something we're able to do. We're glad you're interested in using this button with Strava, and that's feedback you could provide directly to Apple.
I’m using Apple’s Workout app on the watch now. The new version of the outdoor cycling workout on watchOS 10 (currently beta) is really good, fully customisable in what it displays. There are many more data options (integrates with Bluetooth Cadence meter for example or other devices), including showing and notifying you of which heart rate zone you’re in, or want to be in.
It also can be fully integrated with the Action button and Shortcuts, so very simple to use and control. It syncs everything smoothly with Strava, so no loss there.
As a result I’ve completely given up on the Strava Apple Watch App and fully switched to the native Workout app.
If Strava ever catches up with this - let me know!
So sad that this thread is marked as “Solved”.
Wot no news yet?
Surely this is an easy thing to implement? Either this. or better still, please give us some control for Strava with iOS Shortcuts, like starting, stopping and pausing workouts - at least then I can build my own Action button shortcut.
Thanks to everyone who has posted about this idea. At this point we don't have an update to share, but I will be sure to post here if one comes available. Each one of you has valuable feedback on how to improve Strava. We love hearing from you and will do what we can to surface hot topics and trends to our product teams.