Hi Western AZ Mac,
Thanks for reaching out to the community. Do you have another user account setup on your Mac? If so, can the issue with the Contacts App be reproduce under a different user account? Try adding a contact while the Mac is in Safe Mode. Safe Mode helps isolate issues that can be caused by software during startup. Take a look at the steps and article below for Safe Mode.
- "On your Mac, choose Apple menu > Shut Down.
Wait for your Mac to shut down completely. A Mac is completely shut down when the screen is black and any lights (including in the Touch Bar) are off.
2.Press and hold the power button on your Mac until “Loading startup options” appears.
3.Select a volume.
4.Press and hold the Shift key, then click Continue in Safe Mode.
5.The computer restarts automatically. When the login window appears, you should see “Safe Boot” in the menu bar".
Start up your Mac in safe mode - Apple Support
Keep us updated.