doesn't the under consideration period only apply to non-o's based on marriage or other things that might require authentication? Wansn't aware that applied to based on retirement...
The bank is trying to prevent the use of agents depositing funds, getting a letter from the bank and then the agent withdrawing the funds. If there's a threat of freezing the funds to get the letter then agents won't be able to do their thing. Not sure why bkk bank is inserting itself into the immigration process.
30 days is plenty of time to open a bank account. No need to leave country y to get additional years. No insurance requirement, background check or medical certificate. Non-o is the way to go.
Depending on the free at your bank, swift is usually cheaper than wise for larger amounts (more than 200k). Transfer in your native currency, Thai rate for your native currency will be better than your bank rates for Bhat.