@Za ******
Not sure what your misguided obsession with what visas others have and their identity has to do with reading, comprehension and experience. I'm agreeing with you that an extension is simply extending your stay. It isn't a fresh application. Therefore, the docs required for an extension must be based upon the original application route which is soft power in this case. However, a DTV is a DTV. For entry purposes, there is no such thing as a soft power or workcation DTV, they are interchangeable. There is no requirement to be currently enrolled upon a qualifying cultural course or currently employed/in contract. Purpose of entry doesn't require either. DTV being a tourist visa, tourism is and has been accepted as a valid purpose of entry. Other sporting activities within Thailand (not necessarily of a cultural nature) have been accepted. There is a verifiable report of a guy who gave up his Muay Thai Boxing course and reverted to his main sport of marathon running. He was granted entry upon that basis.