Based on the Phuket Sandbox, even lower than that - the 0.3% infection rate there included people who tested positive on the second or third test and who might have become infected after arrival.
I don't disagree - I'm only talking about the terminology!
The term "quarantine" has been used for hundreds of years to describe the method of keeping outsiders separated from the local population until it's established that they're not infected (originally for 40 days, hence the name). You're correct that what's being done during "Test & Go" isn't exactly quarantine, since travelers are waiting for a test result rather than being monitored for symptoms, so maybe that's how Thailand justifies calling the process "exemption from quarantine".
I've done six retirement extensions in Bangkok, and no medical form has ever been required. I've heard that Phuket immigration requires such a form, but the actual regulations don't call for it.
That graphic is from the Ministry of Foreign Affairs, not the Bangkok Post. It correctly (though not clearly) indicates that flights to Buriram must be chartered, not all flights to all airports. And MFA has since reiterated that Thai nationals are NOT required to show proof of health insurance (unlike the rule for the Phuket Sandbox).
Yes, Kasikorn usually insists on a "retirement visa", but they seem to have a binder for staff with examples of what falls under that category - including the OA that the OP has (since it doesn't have the word "RETIREMENT" stamped on it the way an extension does).
If you're talking about a foreign card, you can take 30k at a time from the ATMs of Krungsri, TTB (formerly TMB), and Citibank. CIMB also allowed this, but I think they've gotten rid of all their machines, other than perhaps a few attached to physical branches.
I'm not aware that the location of your bank branch would make any difference to immigration - I've heard of many people who have continued to use accounts at branches in other parts of Thailand after they moved, simply because it was too much of a hassle to change. (From what I understand, no Thai bank will let you just change the location of your account - you have to close the existing account and open a new one at the other branch.)