MacOS Font Book showing only "Last Resort" question marks in boxes?

Hi, I'm on a Mac Pro running MacOS 12.1. Font Book shows most fonts (and I think all of the system fonts) as squares with question marks.

As a remedy I tried clicking "Restore Standard Fonts," which produced the message "Standard fonts were restored. No problems were encountered. Your system already contains the standard system fonts and no others. No changes were made."

Then I tried deleting the font caches using sudo atsutil databases -remove" in Terminal and rebooted. Same issue persists.

I've only noticed it when people send me emails using Futura, which is how I discovered that basically all the fonts in Font Book aren't appearing properly.

Any thoughts or assistance would be appreciated!

Steve

A screen cap of the issue is included.