There is another link worth reading [LIST] Features list for devices - VoLTE/VoWifi/Wificall per-device carrier compatability, two recent posts # 28 and the next one from your part of the world.
FWIW, the “two phone solution” is, I think, a good way of disrupting the collection of your “network fingerprint”.
Late Edit – another perspective …
Australia’s 3G Shutdown - Why your 4G/5G Phone is now Blocked! | James Parker | Medium