Did you enable WiFi calling? I have the same phone and this happened to
me around the same time of the year and that was somewhen not too long
after going to WiFi calling and I used to have the old TuGo app
I have this issue also. If you change phone settings to not send the ID
then it shows Withheld. This problem is that it randomly shows
Unavailable. So I can call a landline 10 times and 7 will show my number
and 3 will show Unavailable