Hello,
I've done that and unfortunately it's still not working for me here.
There seems to be an issue between my iPhone and Mac Mini. It's aware the phone is there (and on the same iCloud/WiFi accounts) it's just dialling out which is posing a problem.
What happens when you dial out, do you get an operator error or does it not even make the call?
Does it work on other devices if you have them i.e iPad?
Does SMS forwarding and handoff work?
Make sure Wifi, Bluetooth, Continuity and Phone Calls (in messages) are turned on on all devices. Also all devices need to use the same Apple ID email because I heard that it otherwise could causes issues.
It's weird I never really have problems with handoff or continuity I just had these 2 weird instances where a) I got an operator error due to the 0 after int. Prefix and b) the Mac thing I described in this thread both which are fixed now
Let me know how it's going I'll gladly try to help.