I've been having an odd issue where, after installing any iOS update (i.e. 17.2) on my phone, the Strava Apple Watch app becomes unlinked from my phone and showing that I need to complete setup on my phone.
Uninstalling Strava from my phone (which removes from watch), rebooting, and then reinstalling Strava on my phone will fix the issue temporarily, but at next iOS update, this will reoccur.
The only workaround thus far has been to uninstall Strava from my Apple Watch, reboot the watch, reinstall Strava on my watch, and then go through setup again.