Some people have claimed that the upgrade to Catalina messed up some of the plists. The plist for Photos is apparently in /Users/bradleyross/Library/Containers/com.apple.Photos/Data/Library/Preferences and the name of the plist is com.apple.Photos.plist (Display with plutil -p com.apple.Photos.plist ). However, I don't have your problem and don't know what to look for. Always make copies of plists before doing any editing, and it's probably best not changing anything.
Can you click on All Photos in the View Menu? If so, what appears? This should give you the same display that you would get from the Photos button.
If you do things like reboot or use Safe Mode, make sure that you close all applications, especially Photos, before shutting down the computer.