Hello gmd39!
Thanks for using the Apple Support Communities!
I see from your post that when you go to Mail > Preferences, you only have the "Font & Colors" pane and nothing else will show. Being able to have full access to all Mail preference panes is very important for full control of Mail, and I want to help you find a solution for this issue.
Check to see if the issue occurs in safe mode on your user account. Follow these steps to start up your Mac in safe mode: Use safe mode to isolate issues with your Mac
If the issue repeats in safe mode, try testing for the issue in a new user account, follow the steps in this article: How to test an issue in another user account on your Mac
If the issue continues to persist, you may need to backup your data and reinstall macOS on your Mac: How to reinstall macOS from macOS Recovery
I hope this information helps you.
Kindest Regards.