correct i thought you could only get a non o applying at an embassy outside of thailand. I have been on a non o volunteer for 7 years with a work permit and now on a covid extension for a year and a half. Still have to take in all the paperwork but now every 2 months not 3. Before every year i would leave the country to go to a embassy and apply again
As a volunteer for many years you also need a work permit to go with that visa which can only be granted with paperwork from where you are volunteering. For extensions you need to provide photos and a mountain of paperwork as proof that in fact you are a volunteer. Immigration will also send out officers and the local police to check that in fact you are a volunteer. Most local immigration offices know where volunteers actually do volunteer. I would be careful