We're several people on Intel chipsets that had BSOD issues with KB5003690.
OP had AMD too, lets wait until she installs the updated update, to see if she has sound issues, this sounds like a seperate issue tho.
Perhaps look into turning off / on WebRTC, try a different soundcard etc etc.
edit:
First of all, either (this is recommended) try making another account on your windows machine, install a completely fresh firefox there, no addons no nothing (DO NOT use the same profile as you do on your main), see if sound works, if not, turn off hardware acceleration in firefox, see if it works. If not, reboot, try again. Log out of your other windows account too, better yet, reboot into the other account (might be other programs what are taking priority / muting video in chrome / firefox)
If that doesnt help, you should probably start a new thread, as I doubt this is the same issue the rest of us are having.
Already did post just a couple above you and on page 5.
"Attn All:
I had the same issue with KB5004945, yet was able to uninstall with success and even better yet was able to hide the update from trying to reinstall using
wushowhide.diagcab. Yes, it will hide and prevent it from installing. You can search for it or go get it at "Major Geeks."
MS longer supplies this from what I understand.
Hope this helps.
Heidi-Ann"
My other rigs are also AMD. Some newer some older with no issues.