No need to reapply. Muay Thai course wasn't gonna last 5 years anyway. Just maintain THB 500k all the time and say you're remote worker, but better have stuff to back that up if they insist on checking.
That OP is an idiot. He can't catch a hint? Immigration will come up with anything at this point to discourage DTV holders from extending. They prefer we exit and re-enter! Expect to see more SURPRISED PIKACHU posts from DTV holder wondering why it's so hard to extend. Meanwhile, some of us never bothered with that nonsense.
Beautiful, thanks for sharing. I'm curious what questions Thai Airways asked, and why did they printout your visa? You didn't have a printout of your own?
All nationalities are eligible for the DTV. So-called "restrictions" only pertain to where some passport holder may apply from. Many from "3rd world" countries should only apply from their home country. Even North Koreans are technically eligible, it's just that it would probably be quite difficult.