Contact an agent in Pattaya, it is usually a lot cheaper than doing it in Bangkok, you can get the bus from Ekkamai bus station to Pattaya, and the same to go back.
select cardless withdrawal at the ATM, and authorise it using the app, it is free for out of area withdrawals, it is usually āļŋ15 for out of area withdrawals, only if you use the physical card.
sounds like you got lucky, they must have been happy with the documents you provided, I believe banks in Thailand are independent businesses, so can have different requirements from bank to bank, in the last two years people have been getting refused a lot, on short term visas trying to do it themselves.
on a post someone stated Mots can't open a bank account for people under 50 years old, I'm assuming it means for people on short term visas, even tho the DTV is a 5 year visa, they seem to be classing it as a tourist visa.
about two years ago, banks either stopped allowing or made it very difficult to open a bank account yourself, some managed it buying insurance, or with a letter from immigration stating it was to get a long term visa, but agents continued to be able to assist people regardless of visa status, but well known agents are now saying this in Pattaya, send them a message through Facebook, if Pattaya is convenient for you, it seems if you're over 50 years old, you might be okay.
Try an agent, but even some very well known agents in Pattaya, are saying they cannot open a bank account, for someone under 50 years old, on any short term visa, even tho the DTV visa is a 5 year visa, they seem to be classing it as a tourist visa.