true. There was a non stop argument from one guy when I said the TDAC can be completed within 3 days of arrival. It can. Including at the airport if absolutely necessary. But after about 20 posts saying I was wrong, I gave up. 🤦
you won't get a bank account with a tourist visa. And you need a bank account for the retirement extension of stay within Thailand. So, if you want you can do that retirement visa in USA, arrive, open bank account, and do extension process when you're ready to move.
the visa is valid 90 days for your entry to the country. Once you enter your period of stay starts. If you leave before you get your bank account or apply for your "extension based on retirement" you'd probably have to start over. I only know what I've been told as I'm doing the retirement route myself. I already have my bank account.