Please provide more details. What exact version of Lightroom do you have installed? The headline of your message indicates that the camera is "unsupported" in Lightroom. What do you mean? Can you provide a screenshot of how they look in Lightroom? What operating system are you using? The more details you can provide the better.
What exact version of LR are you using?
My pictures are looking crisp on my new Mark IV but they look terrible in LR
Define "terrible". Better yet, show us a screen capture. Are these photos edited in Lightroom, or is there a preset applied? Or are you talking about unedited photos? Give us more information!