if you uploaded or shared an .r3d frame and the resulting .dpx frame, people might be able to help you more.
More information on your workflow from camera to final display format would help people help you.
You need to have your vegas project settings correct for the media you dropping on the timeline. Pixel format, compositing gamma, and view transforms is what I am referring to here.
Using Sony “levels” at the media lvl, track lvl, preview or effect level is probably what you are looking for. Set the gamma, and your input and output to get your footage in spec. But you need to understand the project settings in Vegas and level changes you are making through out the workflow.
I would try Epic footage -> RedCineX -> .dpx -> vegas for edit.
or
Epic footage -> RedCineX -> Cineform.avi -> Vegas for edit
or
Epic footage -> RedCineX -> .exr -> Vegas for edit w/proxy for smooth playback. Working in EXR will retain your color depth information from the epic. 10-bit dpx will clip that information.
If your final display output is DPC, that format is 12-bit JPEG2000 capable. So retaining better than 12-bit information will optimize this conversion. But ultimately you need to conform your camera footage to the edit intermediates required, or your final display format.
Mainly I would think your CC would be done in RedCineX, Resolve, or Vegas with the proper display hardware to grade the footage correctly. If you going to work with a CC house that uses one of the Unber pro CC systems, then work with them on the format you need to deliver to them.