You may try to install these packages in a test template to diagnose/check if it helps:
vlc vlc-extras python3-vlc vlc-core vlc-devel phonon-qt5-backend-vlc libvlcpp-devel alsa-plugins-pulseaudio alsa-ucm alsa-utils pavucontrol pipewire-utils pulseaudio pulseaudio-libs-glib2 qubes-audio-daemon xfce4-pulseaudio-plugin pulseaudio-qubes qubes-audio-daemon
Some of them are already installed, some probably aren’t necessary, but you can try them using test template.