Absolutely not. If your country’s embassy won’t do the income affidavit (US, UK, Australia and perhaps others) then your only option is the banked 800k method for the initial visa and the first year extension.
That’s great but very few companies are able to do this. It’s staggering the amount of usually in the hundreds or so. Obviously if one has connections it may be easier.
Maybe best to start a new post asking which embassies will work with less than 6 months statements. Pretty sure Vietnam requires that but the others may not.
in theory you can extend your stay from 180 days for another 180 days once per entry. However in practice it’s just way simpler to “bounce” to another country and return for a fresh 180 day entry.