The next holiday in Thailand is December 31st (source:
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If your current "admitted to" stamp expires on the 1st of January, 2022, I highly recommend applying for a 60 day extension of stay based on unable to travel due to COVID-19 on December 29th. December 30th will be busy at the immigration office, and if you are verbally rejected for the 60 day extension of stay, it will be easier for you to acquire the documents (flight out of Thailand? Letter from the embassy? Whatever else they want) to meet the requirements, or to give you time to depart Thailand on the 4th without paying any overstay fines.
Remember too each immigration office has slightly different polices about getting the extension of stay, and advice about Kanchanburi Immigration Office may not apply to Nonthanburi Immigration Office (for example).