Exactly so why change. The only big reason for many to change is if they want to work legally in a remote role. The DTV allows that while the retirement does not. The main reason I hear for changing O Retirement to DTV is 500k as opposed to 800k.
I did mine yesterday in Chiang Mai. All I needed was passport and completed TM47. I was told I needed TM30 and handed copy over. He just gave it back to me. I was told I needed bio page of passport plus viaa and entry stamp. Not needed. He scanned passport then printed out o0 Day report. About 3 mins. At Jomtien last time I needed all the copies plus paper TM30. Unless they are starting to align then different offices have different requirements.
It took me all of 5 minutes to do my 90 day report yesterday. Depends on office of course. That was Chiang Mai. In Jomtien my max time was about 35 mins
Here was a similar question a few weeks ago. Try and find the thread. When I had to cancel a retirement visa as I was offered a job years ago only the immigration office who issued it could cancel it. Immigration does not issue DTV though.
From other comments many have stated their letter from employer stated specifically they were allowed to work remotely from Thailand. It probably depends on the particular embassy you apply to. As for moving from Ed to DTV others have done it and I do not think the MFA are checking that you have been working illegally in Thailand
I can assure you the process for Retirement Visa is easier than DTV if you apply in Thailand. You can always change if you wish though but if you want to do any work remotely in Thailand the DTV is the way to go.