microphone and speakers gone after last Catalina update

If you didn't create a bootable backup (Carbon Copy Cloner, SuperDuper! etc) prior to the update, I think you're going to have to reinstall: How to reinstall macOS - Apple Support (Make sure you have a backup.)

Before that, one thing you can try is to create a new Admin User Account and see if they show up there. System Preferences > Users & Groups > click the lock > enter password > click on the + sign to create the new account > check the box to make it an admin account > restart and log in to it to see if mic/speakers are there.

Hi,

Do you mean they don't show up at all in System Preferences > Sound, or they're still there, they just don't work?