dear Mark,
after having read all the previous solutions I can ad a complete different one. having two computers with Realtek and W.10, I regular had problems with sound. mostly it effected in combination with a conflict of my virusscanner and the computer locked.
after the restart all functioned well. also after often used the sleepfuntion the audio gave disturbances. and it all was in W.10. for many years. it gave me the impression that this audio is in itself malfunctioning.
at the end I uninstalled the virusscanner and hoped with W.11 that all should become "perfect". what a disaster it became with no sound!
now I wrote Acer to come with a solution and am waiting for their answer. what will they say/do? they are the manufacturer of the laptop and a part of their product is not working...
Jacques