If you have 800 000bht each maybe get an agent to open your bank accounts as that the hardest part about 5000bht bkb or Yellow bank you can sent larger amounts and they show as international i use Wise then do the rest yourselves 1900 non o 90day then 1900non o retirement permit 1 year + 500bht for photos photocopying & bank statement
not good for travelling to any of the island that time of the year that's why the flights & hotels are cheaper because it's rainy season (monsoons) its not good idea to be in or on the water big waves & strong currents.Come November-May worth spending the extra cash to have a good holiday
I wouldn't normally recommend using an agent for anything but maybe for opening a bank account as its a very time consuming thing to do and costly if you have to take out banks own insurance
Use Bangkok Bank or Yellow bank as you can deposit more than 55k at a time and they both expect Wise international transfer which show on your statements
Immigration are just trying to get people who are abusing the tourist Visa with extensions and going in and out the country constantly. Not people who are here for only a few weeks