The big daddy in bike lock brands, this lock sells for $150 locally. It weighs over a kilo and will secure your bike to “requires a battery powered angle grinder to steal” levels.
Comes with a pretty good mounting bracket and additional cable to secure your front wheel (I have had an enterprising sort saw through the cable on mine, but the bastard didn’t get my bike!)
The only downside is depending on the rail you’re locking your bike to, the size can make it difficult to get your back tyre and frame secured at the same time.
NB Kryptonite’s included stolen bike insurance does not cover Australia.
I got these for about 70ish a few years back.
They've been the best thing.
Never had my ebike stolen since.
In some countries in the EU they used to (or maybe still do) come with a level of insurance for if someone breaks through them and gets your bike.
But unfortunately that does not extend to Aus.