unsure what travelling here hundreds of times and 5 hour flight has to do with it, but I thought you said you got an agent here to apply for your visa?
Up to you, but if I was doing something illegal i would not advertise it on Facebook.
You are clearly looking at the wrong visa, you need to look at the non O visa not the non OA.
you don't need insurance to apply for a visa outside Thailand. That is the non OA visa that very few use now. Most people get the non O visa instead, before they come to Thailand and that way you can open a bank account without an agent.
Using an agent to deposit 800,000 baht for you Is illegal. If the immigration officer is investigated all of their visas are cancelled and you will be deported (yes it does happen I have spoken to 2 people this happened to). My advice would be to delete your answers on here and get a legal extension next time.
non oa requires criminal checks and annual insurance. Non o requires proof of funds, so to extend each year you need 800k baht in a Thai bank account. Most people choose the non o, as you don't need the specific insurance and you don't need to leave Thailand to extend year on year.
it is a very easy process. Each immigration office ask for slightly different things, but this is roughly it. One form to complete that asks questions like; date you arrived in Thailand and passport number etc.
You need lots of photocopies of everything.
A lease contract for a minimum of 6 months (I think this varies between offices) and a hand drawn map of the location. Some passport sized photos. Information from your bank (they know what is required). A payment of 1,900 baht.
It has taken me less than an hour each time to get my visa and then extensions each year 3 times, so it definitely is not worth paying an agent.
if you start depositing 65,000 baht every month into your Thai account, for the second extension you should be able to extend using that as proof of funds and then withdraw the 800,000k.
You have done the difficult part already by opening a bank account.
Ensure your money when transferring is recorded as coming from overseas. If you use Wise I think the code is something like "funds for long term stay in Thailand ".
If you don't want to open an account in Thailand, go inside Krungsri bank with your passport and debit card to withdraw cash. There is no ATM fee and the withdrawal limit is much higher than the ATM (I can't remember how much). You get the exchange rate of your bank in your country. I use Starling bank debit card and get a really good exchange rate.