@Helio ****
I have NOT seen anyone be formally denied a 60 day extension of stay based on unable to travel due to COVID-19 yet (as in, they got the 7 day extension of stay denied stamp).
I have seen dozens of reports of people at Changwattana, Nonthaburi, and other locations with lots of tourists being verbally rejected. In most cases, the immigration officer will issue the extension of stay IF they show a valid flight out of Thailand within 60 days.