So, I have seen some very unusual suggestions, and the one that left me scratching my head was deleting contacts from iCloud. I don’t use iCloud, so this would not be a fix for me, but if it worked for you, great.
Now, then one that did sound like it was getting closer to the root cause is Bluetooth.
I use Bluetooth at least 5-6 times a day. Some connections are for things like the speaker when I shower, or my car system for phone calls. I also use a could different headsets as well.
Now my initial problem was no notifications, but it got to the point where I wasn’t getting audio at all on calls I answered. They couldn’t hear me, and I couldn’t hear them.
my problem was fixed after a hard reboot, and since then I am still using Bluetooth, but I am wondering if Bluetooth is not working properly and not releasing the “reservation” of a previously connected device. Like if I used a headset, and turned the headset off, but the phone acts like it’s still connected, I would lose audio for calls.
granted, this is speculation, but makes more sense than iCloud blocked contacts.
So let’s add one more step to the procedure of the reboot.
first, put your phone into airplane mode, then shut it off.
power on and make sure that you are no longer in airplane mode.
check the silent switch
check do not disturb
check volume levels
test.