After Android 10 update, LED notification do not work anymore. I did Factory Reset - not helpfull. I booted phone in Safe mode - not helpfull.
I discovered, it has some connection to EdgeLighting. If Edge Lighting is Off, LED notification is not working at all.
If EdgeLighting is On, than for supported apps by EdgeLighting, LED is working, too (ex. Viber, Messages...), but it doesn work for Missed call.
I have the same problem now. It doesn't work anymore after a few reboots and there is no way to solve this problem. This is an update bug and samsung must fix it !!!