I wonder how you would be able to apply mitigations on carriers (like T-Mobile) that have turned off their 3G service. If you don't have a carrier which supports 3G (or lower), don't you need VoLTE turned on in order to make & receive voice calls?
It works for data and calls, not fast but since not much falls to it anymore it seems to rarely be congested. My coverage with it was always better than with their 3G network and I used it years past its prime for conserving battery (until they deployed low-band LTE). You need at least a 3G device to use new sim cards to get on 2G but if you've been a customer a long time and you haven't changed cards, there are still activated ones in the wild that work with old devices (I was able to get calls and SMS to work on a t68i, but needed to use a w810i to get working data when I tried a few months back).
