Thomas,
My C80 screen went gray several months ago and I use it primarily for radar. The screen sits forward of my shifter and is angled up where it is easy to see. My chartplotter on the dash is Garmin and it is tied to NEMA 2000, along with my AIS, auto helm and outboard. I was contemplating changing my C80 to a Garmin, along with the Garmin radar antenna, but once I looked at the out the door cost of the components, I chose to just replace the C80 screen...
I too looked around and found many screens for sale on eBay, but ended up purchasing a nice one that was from a pilothouse boat (screen was always inside) and the boat wasn't very old. The seller was upgrading everything to Garmin. I was able to purchase it from him on Facebook Marketplace for $250, which included shipping. It was wonderful just to plug in a screen, without going through the wiring drill.