When creating a new Lightroom classic catalog the images do not preview. I have to quit Lightroom altogether, then reopen the catalog in order to see them. This has been going on for months.

I’m not sure I understand what you are saying. If you create a new catalog, then that catalog will be empty and won’t contain any images. So when do you encounter this problem? When you import images into this catalog for the first time? Or do you mean something else when you say ‘creating a new catalog’, such as exporting as catalog?

What happened if you import images to the new catalog? What do you see in the library view?

Check your monitor profile: How do I change my monitor profile to check whether it’s corrupted? | The Lightroom Queen

Try to reset the preferences of Lightroom:  How to reset Lightroom Classic preferences (adobe.com)

It's recommended to backup your preferences before you reset the preferences to the default settings: https://helpx.adobe.com/lightroom-classic/kb/preference-file-and-other-file-locations.html

Please provide a copy of your 'System Info'. This can be get from the Lightroom menu item Help > System Info. There's a copy button in the System Info dialog. Press this button and paste the info into a text file and attach it to your next forum post.