Didn’t they stamp your passport to advise your application was under consideration and return to that office on a particular date? That’s my experience and I have to return on March 30
the official order of visa extension is the optional 30 days is issued first then the 60 day Covid extension can be applied for if required. If Covid extensions are being granted before the visa extension then the issuing officer isn’t following protocol.
You can’t skip the 30 day visa extension because that’s the order the extensions are granted.
You don’t need an appointment.
You go to the nearest immigration office to where you are living, with proof of residence.
Covid extensions are for anyone stranded in Thailand due to the pandemic, Covid extensions are being provided up to March 30 and no one knows if the program will be extended or not.