Pretty sure it has to be a Thai bank account or you need a letter from embassy verifying monthly income. If I recall correctly the Aust embassy won't issue such letters, so you'll need to revert back to money in a Thai bank or find an agent to grease the wheels for you.
why should they care? Your hotel will register your details after check in anyway (unless they are dodgey) and if someone is out to be nefarious, chances are they will just lie on the incoming card anyway.
Visa fee is up around $9k, $3k+ for an agent then allow another $1k for police checks, translations etc.
I did the application for my wife without an agent but if you want to do that be prepared to put in countless hours of research to work out how to put together a quality application.
My wife had a multi entry tourist visa, so we did the partner visa application onshore. We got the approval very quick and without any RFIs.
We were married before she moved here and then by the time of the stage 2 application had a son.
my parents arrived December 30 at BKK airport under the Test and Go scheme and got it. That slip is needed to get the PCR test for free.
Can you try talking to the Test and Go hotel that you came in through and see what they say? I was under the impression they have access to some sort of web portal for this quarantine related stuff.