I originally posted https://zentalk.asus.com/t5/zenfone-10/volte-support-on-canadian-carriers/m-p/393219#M845 a while back and also had no luck with Asus support or my carrier(s).
However on a whim, I tried force-enabling VoLTE today with the *#*#3642623344#*#* trick and it worked! Placing a test call, I saw my mobile connection remained on 5G (instead of downgrading), and the VoLTE icon now shows in the status bar. This doesn't persist thru a reboot of course.
I assume something must have been changed in a recent software update, and/or my carrier (Freedom Mobile) have changed something on their end, as this trick didn't work as recently as ~6 months ago.
CC:@Nero9937 in case this also works on your device now.
