kennedyt: not on my Nokia 7.2, i needed to disable VoLTE to send an SMS, Received SMS OK with VoLTE enabled.
That's interesting, and good to know. Similar experience with my Xiaomi mi9se (you can use a dialler code to enable VoLTE with most Xiaomi phones). Hopefully SMS over IP gets sorted sooner rather than later.
Oddly, there have been some instances where this has successfully sent SMS (see earlier in this thread) but it hasn't worked the last few days (I give it a test every now and then and manually disable VoLTE to send SMS as the call quality and consistency is so much better even when I've got great 3g coverage).