Hey srdr_ckr,
This page says it best, as far as what you can expect: Apple Watch - Carriers - Apple
Cellular service support.
To cover the LTE and UMTS bands used around the world, there are two separate cellular models for Apple Watch Series 8, Apple Watch SE, and Apple Watch Ultra. They have been optimized for use in the country of purchase, and not all models work in all countries or regions. There is no single model that supports cellular service worldwide. To see which carriers in your country or region offer cellular service for Apple Watch, refer to the chart below.
Scroll down to the section which has the newer apple Watches for Australia and other countries. This section will tell you which Apple Watch model to purchase.
Keep in mind, if the cellular ends up not being compatible with another carrier, you can always use it without the cellular connection, as a GPS only model, and just keep your iPhone nearby.
If your iPhone isn't nearby, and Wi-Fi is not available, then the section titled "If your Apple Watch can't connect to Wi-Fi, cellular, or your iPhone" on the below page, will show what you can still do with your Apple Watch:
Use your Apple Watch without your iPhone nearby - Apple Support
Take care!