Apparently, they've been rejecting more and more applications lately if they are based on a recent business registration.
They suspect people are just registering to get the DTV. Without a track record or any clients, it's tough to get the DTV approved as self-employed. For me, it was easy since I'm employed and have been with the same company for over 15 years. The DTV could therefore be issued with a clear conscience.
The agency I used says all the Thai embassies/consulates in Germany operate on a similar, "normal" level; neither particularly lenient nor super strict. (according to its experiences).
I knew fundamentally that I met all the requirements virtually perfectly.
So from the very beginning, I strived for efficient processing, which included my aim of avoiding any requests for additional documents from the consulate.
Therefore, I researched in advance precisely which documents exactly were successful for remote work applicants.
With this approach, I just wanted to save both sides extra work. And it did indeed succeed.