Yup it’s that easy. Check on the roaming prices though as depending on how long you’re staying it might be cheaper to get a temporary prepaid Australian number.

Otherwise yeah just turn on roaming and you’re golden.

That’s pretty much exactly what I have done. I’ve hosted Plex, and Matrix in the past. Plex I will host in the future but Matrix was too much for me to host on my own, but the experience of setting it up myself was definitely worth it.