There are videos on how to disable it permanently
Mine has a setting for sound off, which is great because it is a horrific loud beep, three times that doesn’t stop even if you try to interrupt it with a button or by opening the door. Anytime we have a power outage, it resets and I turn that damn beep off before I even change the clock because it annoys me so much.

THIS NEEDS TO BE MAINSTREAM.

There is very little reason that with the digital behemoths that microwaves are now, that a simple “sound off” setting can’t be done.

I would also love a “sound off for this cycle” option, but that might be being too needy

There is very little reason that with the digital behemoths that microwaves are now, that a simple “sound off” setting can’t be done.

Most microwaves already have this feature, it’s just not obvious how to use it. Read your microwave’s user manual.

mine has a way to change the clock to 24h and the ability to calibrate the hot keys, but sadly doesn’t seem to have a sound control.
Well, time to disassemble it (safely discharge the capacitors!), find the beeper on the control board, and de-solder it.