I've had a Galaxy Watch3 for a few months and it worked great with my previous Pixel 3a on Android 12. Samsung Health sync'd instantly and no issues with connection. I recently upgraded to a Pixel 6, and now syncing with Samsung Health is patchy. At first I didn't notice an issue, but now manual sometimes results in "Can't sync with Galaxy Watch3", typically for hours at a time, then it later starts syncing again with no obvious change to setup. No other connection issues between phone and watch (the watch is definitely connected via bluetooth and otherwise communicates normally). No change in use or settings versus my previous phone. I tried rebooting etc. Double checked and turned on all permissions for Samsung Health. Also tried uninstalling and reinstalling the app on the phone. The first time I sync, the phone picks up my latest steps/workouts/etc, but after that it syncs very intermittently.
Any ideas? I suspect it is an issue with the Pixel 6 + Android 12 not talking to the Samsung Health app correctly but curious if it is a known issue.
Experiencing exactly the same issue with Pixel 6, Android 12 and my Galaxy Watch Active 2. First sync after restarting both devices, resetting etc is fine, but after that I simply see "Couldn't complete sync with Galaxy Watch Active2".
Am going to give this a probably by now... I note the Pixel 6 has a plethora of Bluetooth synching/connecting issues. I'm experiencing the same issues...kind of makes me wish I had gone with the S21 vs the Pixel.
Minor progress - some combination of clearing the app cache and doing a force stop of Samsung Health (both via Android settings) usually gets all data (steps, activities, HR, etc.) syncing again. But like other solutions, it only works for ~24 hours at a time. No obvious fixes yet from either Google or Samsung.