You've probably been listening too closely to the wrong people ... Your D500 could easily be the last camera you need this lifetime, certainly it's barely used at 10,000 clicks. But, we all know the grass is always greener when captured with a mirrorless camera.

Consider your current Nikon lenses and whether you want to dump them all or retain DX lenses on a cropped Z50 or FX lenses on the various Nikon FF mirrorless options. After a lifeline of Nikon, the reasons to change to another brand are not compelling, unless again, you've been listening too closely to the wrong people.