Sound on internal speakers stops working on MacBook Pro

Audio stops working, 2021 MacBook Pro M1 restarts whenever it goes to sleep or the computer closed. Like others… This is not caused by any of the obvious things (accidentally muting, sound turned down, wrong device selected, etc.), and does not affect the earphones (which work if I test by plugging them in when I’m having the problem; when they’re then unplugged, the speakers continue to be silent even though the audio program material is still running). In System Preferences, everything looks fine (same as when it’s working properly), and switching back and forth between devices doesn’t fix it or change the volume or toggling mute. However, it does not always start working properly after a system restart. I’d like to find the cause of the problem and fix it permanently rather than have to apologize to clients. Latest OS 13.5. Doesn't matter if apps are running or not. Youtube videos do not play in browsers when the sound not working.