Jnance49,
Marvels are not MFi AFAIK so my guess is that you should have three Bluetooth pairings (if your BT connection configuration is anything like Android, which I have).
Do you have 3 BT pairings, probably 2 for the R and one for the L?
Also, in your sequence of events to fix it, I didn’t see “delete BT pairings”. After deleting the app, you should make sure the pairings are deleted in the wireless/BT settings.
The non-connection of two of them is not surprising. Only one of the R pairings should be connected (for phone call and audio streaming). When you open the Phonak Remote App, then and only then will it connect to the other two R and L pairings (which are BLE control pairings). Normally these two R and L pairings will show not connected.