As a test launch Photos with the Option key held down and create a new, test library. Import some photos and test to see if the same problem persists. Does it? This tells us if the problem is limited to your current library or is more wide spread.
Then open your current library and see if it will open fully.
Next, if the problem persists, log into a basic admin user account, Set up users, guests, and groups on Mac, and see if the problem persists. This tells us if the problem is limited to your user account or is system wide.
Lastly, boot into Safe Mode according to Start up your Mac in safe mode - Apple Support and test to see if the problem persists. Reboot normally and test again.
NOTE: Safe Mode boot can take up to nearly twice as long as a normal boot as it's doing the following;
• Verifies your startup disk and attempts to repair directory issues, if needed
• Loads only required kernel extensions (prevents 3rd party kernel/extensions from loading)
• Prevents Startup Items and Login Items from opening automatically
• Disables user-installed fonts
• Deletes font caches, kernel cache, and other system cache files
