You should now be able to resolve this issue by updating your iOS to version 14.2.
The 1.5.0 app release is causing issues syncing activities from the watch app to your Strava account. Another update will be released to resolve activity sync issues. Thank you for your patience.
Version 1.5.0 is now available in the Galaxy Store. Please update your app to resolve the crash issues with the previous 1.4.3 release.