I agree with the others - Evie and Chargefox are the ones to sign up for. You are probably aware, but Tesla uses CCS2 here, and so Teslas can plug into any third-party fast charging network without needing an adaptor.
Evie runs its own network and is responsible for maintaining the hardware. Evie has more than double the number of sites that Tesla has (201 sites/463 plugs for Evie vs. 89 sites/506 plugs for Tesla) but Tesla has more plugs per site than Evie. Evie’s reliability has improved a lot over the past year, but their site at Taree (which is about an hour’s drive south of Port Macquarie) has had regular problems. So always check their App &/or Plugshare before travelling to see if a particular site is working.
Chargefox has only a small number of its own fast charging sites, but provides the backend billing and session management for a number of other networks, including motoring organisations such as NRMA (in fact Chargefox is now owned by Australian Motoring Services - which in turn is owned by Australia‘s 6 motoring organisations). So the “branding” on Chargefox is more confused - they will plaster their logo on a site even if they don’t own it - and infuriatingly NRMA sites do not appear in the Chargefox App
I suggest you look at Plugshare and filter by “Tesla (Fast)” and “CCS/SAE” plug types to see what fast chargers are located in or near locations you might stop at or spend any time in. For overnight AC charging, filter by “Tesla” and “Type 2” plug types.
Enjoy your trip!