I just updated Spotify Desktop for Mac to version 18.104.22.1683.g9f48828e and after restart my library does not show any artists anymore. Just a blank page with a button to "switch to browse" - see attached screenshot.
All saved albums are still displayed in my library, though. Just the artists are gone.
On my Android phone the artists are also still there.
I have the exact same problem in the Czech Republic. There were some artists in my library right after I updated the app, however, they were sorted randomly. When I tried to sort them alphabetically, it didn't work. After I restarted the app, the artists were gone.