Anyone who has had any kind of non imm at any time is not eligible. Anyone who entered with VOA is not eligible. Anyone who entered with TV or visa exempt may apply for a COVID extension. The immigration officer will decide whether or not to issue said extension. Currently last day to apply is March 25th.
Ok, so you applied for and got a 30 day tourist visa with your Sri lanka passport then extended for 30 days then applied for and was granted a 60 day covid extension twice. As far as I can see, theres no reason why you can't apply for another covid extension... have a plan B as the Immigration officer may ask why you've been in Thailand for nearly 180 days... good luck
I pay my taxes here in thailand monthly. This may not be the definitive answer, jut how my accountant does it. I would make an appointment with the business accountant and get an answer directly from them.
not asking about past 2 years. people have been doing visa runs to Cambodia for the past couple of months. Singapore open a VTL with Thailand from 4th march. Vietnam planning 15 March. Others may follow.