Which bank should I approach to open an account in Chiang Mai for my retirement visa?

Leave get the non-o come back open your account deposit 800k after two months apply for the one year extension

If you got rejected from DTV maybe because you were in country. Do you have the 800k to stash in the bank. I think Bangkok bank is required to keep a lot longer.

Hey , can I ask why was rejected ?

Once you have your actual non-O visa, then you can get a residence certificate from immigration and head to a bank. Kasikorn and SCB would be the other 2 biggest ones that foreigners choose that also have the largest limits for Wise transfers into Thailand.

You still might need to try a few branches of whichever bank you choose, as each branch manager sets their own requirements and may be more or less friendly to foreigner accounts.