Hello & welcome!
We don’t really do this… this isn’t reddit 
You probably want to keep an eye on this issues in the RT bug tracker: Support for JPEG-compressed DNG files · Issue #4285 · Beep6581/RawTherapee · GitHub – looks like it is still open.
If you can bring coding resources, that would be sublime, the code is open so people are free to get it and hack away!