Get online support
Thanks for that @Dropbear087 : I tried it out and the reply I got was "Thanks for using our 3G device checker. Unfortunately, we're unable to confirm if your current device is compatible with our 4G/5G network, including its ability to make emergency 000 calls. Please contact your device manufacturer for more information. NOTE: Unless your call is for a legitimate emergency, DO NOT call Triple Zero (000) to test your device.
Since I can't test calling 000 for the obvious reasons, I wanted to wait for the 28th and see what happens. But since TPG is doing a block automatically and my device seems to meet their criteria's on Volte and 4G, hence why I want some kind of confirmation from them as to what is going to happen and what method they are planning on using to decide "unsupported" devices.
It's not network specific because it's a service proved by ATMA:
Check My Device - AMTA | The Voice of the Australian Mobile Telecommunications Industry
If your device shows VoLTE next to the signal bars then it's obviously VoLTE capable, however you may need to update the firmware perhaps and also enable WiFi calling in settings. Hopefully you'll get some clarification from a mod here as to what will happen before 28th Oct. Good luck.