How long can you stay in Thailand after resigning from a job while holding a non-B visa and work permit?

it works like this

IF you're still on the 90 day stamp you got from the Non-B (either inside the country when you had it issued OR that you got when you entered thailand) and you quit your job you can stay until that stamp runs out

BUT

IF you are on an "extension of stay" based on employment (that you got from the immigration office) as soon as you cancel your work permit you need to take that receipt and the documents from your company and GO cancel your extension.

There is no "get free time due to covid" there is no "get a tourist visa" inside the country.

Once you cancel your current extension you have two choices pay 1900baht get a 7 day stamp that says you will leave the country in 7 days OR pay 1900baht and apply for a 60 day covid extension

There is no tourist visa available in country

The big question is are you on an actual non-B visa or an extension of stay?