pycom’s LoPY which has development boards and OEM modules. I use them over in Perth.
Certification? Not sure anything has ‘official’ AU915 certification. Happy to be corrected.
Perhaps @Maj can provide a little better advice.
I would not use AS923 in Australia - not legal as they smother some telco bands. I use Heltec Cubecell and Dragino with great results - these do not have certification. I have tried quite a few other boards and have had problems with drivers not written for AU. That said I use a RAKwireless RAK7258 gateway with a full wave antenna mounted on a 14m tower. If you want a more professional equipment go for the RAKwireless products as they just work.