Sound on internal speakers stops working on MacBook Pro

The NVRAM article doesn't apply because this is not an Intel-based Mac (see https://support.apple.com/en-us/HT204063). The SMC article doesn't apply because for Macs with Apple Silicon, the procedure is just to restart the computer (see https://support.apple.com/en-us/HT201295), which we've already done (see above).

Thanks, Neil22R, I know how to contact Apple Support.

With Apple support, if you have an unusual/atypical/new problem, you usually spend a lot of time getting to the point where you're in contact with somebody who understands the problem, and then, one of the first things they want to do (after you've tried all the known remedies) is have you reproduce it so that they can study it. That's not practical for me in this case, because when it happens, I'm usually in the middle of doing something important (since that's the only time I use the audio through the built-in speakers), and I have to restart my system (which makes the problem go away for a few days or so). My expectation with support is that they will say "if the problem happens again, just restart your system and you're good to go.")

So, I came to this forum in case it was something for which there was a known solution. When I first came here, I found that somebody had posted a question about this problem many years ago, and while there were over a thousand people who'd clicked the "I have this problem too," there was no solution. That original post was old enough that it was no longer possible to respond to it, so I posted a new one.