I don't know why, but I checked my latest changes in my home directory and found that .config/gtk-3.0/settings.ini and .gtkrc-2.0 had the following change:

-gtk-icon-theme-name=Papirus-Dark-Maia
+gtk-icon-theme-name=breeze-dark

Going back to the Papirus-Dark-Maia icon theme solved the audio and video problem. However it didn't solve the bluetooth output, and vlc video stopped working.