That's interesting. I haven't had any problems with the quality, just color shift and gamma.I've read that Resolve's exports for MP4s and .movs aren't the best for image quality and color grading. I started exporting out of Resolve in DNXhr then bringing it into Handbrake and converting that into an MP4. It also brings the file sizes down a lot.
There are some threads about it on their forums, it takes longer, but I was noticing the videos coming out cleaner quality wise.
The same happens in premiere pro.
Final Cut pretty much nails it right out the box with their default settings.
The former programs are set up for you to actual assign the correct color space and gamma tag for the export so if those are wrong your image will be off.
I'm diving deeper into color settings now. Really learning everything has to be calibrated for your camera's color science, your monitor's color, and even learned that your actual computer has its own settings for color management. To get the best image, all of those things have to be set properly. Most users won't see the difference but when you stare at footage full time, those shifts in color and gamma become easily apparent.