Maybe Phuket would be better than Bangkok but looks like you have already raised red flags ,up to you to take the chance or not just remember to have everything in line ,return flight ,proof of accommodation and 20,000 baht in money
a guy brought you there ,and you don't know him ,he must be scamming you or you asked him to go with you from an agency or what ? Sounds dodgy ,go to the police if it's not right
I opened a new account with SCB two months ago and they only asked for a 500 baht deposit to open an account but I put in more , back in 2013 when I opened an account with Bangkok bank they asked for 2500 baht for years insurance policy
Wouldn't be the first time I actually had to show the Grab taxi driver where to go and watch if you have online account as last month one Grab driver charged me full fare and didn't even pick me up from location but it was a no access zone on a Saturday night ,only supposed to charge you 30 baht if it's a no show
Come on 60 days visa exempt and try out different places in Thailand and see the prices of everything,then decide what you want to do ,I would never think of retirement to any country unless I had been there a few times already for a few months living there to see I liked it or not but different people have different ideas