bear in mind after ASQ in Bangkok she will also need to do home quarantine in Chiang Mai...at least under current rules anyway. So a month of not going outside...
Amnesty is long gone. Unable to travel extension is available for 60 days with the last date to apply for this being, I believe, 29 January 2021. After this no one knows what will happen but I have seen one well respected person saying on FB visa groups that in order to get future extensions you will actually have to provide evidence you cannot physically leave Thailand. That's not confirmed yet.