- Edited
other8026 , it appears the issue might be affecting people with the Stock OS too if they've updated to a post QPR2 release.
This is not true. I have confirmed that the issue with Samsung watches does not occur on the QPR2 stock OS. While you are correct that the Samsung Wearable app is really buggy, it does work on stock OS.
On GrapheneOS, the watch can only be connected to the phone during pairing (either directly in system settings or with the Samsung app). After disconnecting the watch, it cannot be connected again without removing it from saved Bluetooth devices first. The phone constantly tries to connect to the watch, as can be seen by the Galaxy Watch constantly jumping between the 'connected devices' and 'saved devices' sections in Bluetooth settings.
This strange behavior is exclusive to GrapheneOS and has been reported by a few other people here.