Fenix 5 Plus:
Before I had a Samsung A5 (Android) and all went well. Since I have a Samsung A53, the optical signal, that the phone is around works well, but the phone does not utter a sound.
This is function is very useful, but I also could not find a setting in my mobile, which is wrong.
Sometimes it worked, but now it has stopped totally (except for "opticical" message.
To search the watch by phone works well.
And yes: Bluetooth is connected.
:)