DTV is not issued for those who work away from Thailand fifo etc you would need to meet one of the criteria,s to get the DTV other than your offshore work
You could do what I did. I got the OX visa leaving my money in Australia. I travel to Thailand 2 weeks every month, still working fifo on 2 and 2 roster. Some don't like to suggest OA or OX due to the insurance requirements I personally like having health insurance plus I have a yearly travel policy.