Thank you for all your suggestions. It appears I’m not alone in having this problem. As I wrote in my original post, the easiest and quickest fix I’ve found is to run the Bongiovi installer. Sound comes back near the end of the installation. It would appear that ‘something’ disables a necessary component of Bongiovi DPS. However, I recently had the bright idea to give Bongiovi DPS full disk access in System Preferences/Security & Privacy. It’s a bit of a wild card and might have no effect at all but so far I have not lost sound.