I can't view Nikon Z5 NEF (RAW) thumbnails in Photoshop CC v22.2. They just come up with the basic NEF symbol. I know Camera RAW supports the Nikon Z cameras, so what's going on? I paid good money for this camera, partially for the Nikon color rendering, and I don't want to convert to Adobe's DNG format. If Adobe can't fix this I'll just stop using PS and use Nikon's new NX Studio. It isn't as comprehensive or flexible or fast, but at least it's faithful to the camera settings and it does come with a monthly bill.
Just for clarity - which thumbnails are you referring to?
Nikon Z5 files can be opened in Camera Raw 12.4 or later and the current version is 13.2 so you should have no problems in opening them. Bridge should also display them correctly provided both Bridge and Camera Raw are up to date.
If you are referring to the thumbnails in the dialogue you see in File > Open then that uses the operating system (e.g. Windows 10) to display the thumbnails so your operating system would need to support the thumbnails for your camera.
Not a Mac person, so pardon my ignorance - but are raw file icons even supposed to look like that? Are you sure some other application hasn't taken over the file associations (or whatever it's called in MacOS)?