I am category 1. Pre-COVID, I was returning to Oz about every 6-7 months for 4-6 weeks, then going back to Thailand for another 6-7 months.
I get my pension paid fortnightly into an Australian bank account. I usually let the account accumulate to $10,000, then transfer to a Thai bank.
I don't notify Centrelink when I have returned, Border Force does that. The supplements are usually restored after a fortnight or two has elapsed.
I notify Centrelink when I leave, the supplements cut off after six weeks. I had this pattern of travel for about ten years, until COVID messed up the world.
I have not submitted a tax return for 3 years.