What are the key requirements and options for obtaining a Non-immigrant O-A retirement visa in Thailand for Australian citizens?

I am an Australian citizen planning on retiring to Thailand (Chiang Mai) in April next year.

I am aware of the requirements for a Non-immigrant O-A longstay retirement visa and that is the one I am pursuing at the moment. I note that some embassies globally are increasing the requirement for monetary deposits to a Thai bank and/or monthly income amounts.

I am also aware of the requirements for elite, 5 year retirement and STV (if it still exists).

However, in order to cover all my options, I am particularly intrigued with the TR60 (+30) visa with the option of applying for a Non-immigrant O visa based on retirement within the initial 60 (possibly 90) day stay.

I would like some clarification on the following:-

a) the reporting process during the 12 month period;

b) the insurance requirements (including for covid) whether it be travel specific and/or health specific;

c) Is it single or multi entry - I ask this because there is a possibility that I will need to return to Australia within the initial 12 month period).

I already rent a room in a guesthouse, have a partner who owns a business and I am the ATM.

All constructive comments appreciated. If there are any Aussies that have gone through the Non-immigrant O visa process I would certainly welcome any comments/experiences/setbacks etc.

Cheers!