You can extend no problem. Save yourself some time by filling in STM.2, TM.7 and acknowledgement of penalties for a visa overstay beforehand. They’re all available online.
Gotcha! When applying for METV, the embassy asked for flight tickets to Thailand. I see no info on this for DTV visa in required documents. Meaning, no flight tickets are required if I apply for DTV?
Thank you! Very helpful info. Is it going to be odd for the immigration officer if I extend my visa exempt after 30 days, even though I have a METV granted? Will they have issues when I fly out on my last day of visa exempt to fly in and enter using my METV?