the BKK website has it listed as a requirement though my experience is the branch managers have some leeway depending what documents they ask for if you are unable to provide
Regardless of which bank you use (I opened an account with Kasikorn) make sure you select the "funds for long term stay in Thailand' option when you use Wise if you are transferring funds in anticipation of getting a long stay visa. Immigration requires funds to come from a foreign transfer. I have been happy with Kasikorn and found them the easiest for me to open an account with. Bangkok Bank is probably the most friendly for foreigners though they require a notarized signature from a local embassy to verify your home country address. of course you can always use an agent and skip that part.
Bangkok doesn’t require the 2 month period for the 90 day non-o, only for the year extension. Still have to have the 800k baht in the bank transferred from a foreign entity before applying is all.
ah ok good to hear the agent is helping you out. It’s actually not so hard to do the whole visa process one’s self but an agent can take the stress off it for sure. Enjoy your time here in Thailand!