Clarification for future readers of this post that might be considering Ubuntu Touch in Canada: All 3 major Canadian networks have stated that they're maintaining 3G until December 2025. Different story in the USA, where at different points in 2022, the major networks discontinued 3G.
In Canada, Ubuntu Touch is very much usable as a phone. Telephone calls, SMS, MMS photos, audio, and video all work as expected for me. (Group texts do not, and MMS has caused me plenty of headaches in general, though I think I've got a stable setup now.)
Hopefully VOLTE can work soon. I'm much too inept to be of use in that quest other than to keep donating to UBports and crossing my fingers. My enduring gratitude to those working to make UT better. It's already improved considerably since I started using it in late 2020.