One of the Nova developers stated the following:
[...]i am aware of the issue that inolves hdmi audio, it's not communicating properly with the devices on a kernel level and by default thinks the headphone jack is carrying audio, as a temporary solution you could connect a speaker to the 3.5mm headphone jack to get sound
Another user stated the following:
i found disabling pulseaudio, installing and enabling pipewire/pipewire-pulse did the trick
sudo apt install pipewire pipewire-audio-client-libraries gstreamer1.0-pipewire libpipewire-0.3-{0,dev,modules} libspa-0.2-{bluetooth,dev,jack,modules} pipewire{,-{audio-client-libraries,pulse,media-session,bin,locales,tests}} -y
systemctl --user daemon-reload
systemctl --user --now disable pulseaudio.service pulseaudio.socket
systemctl --user --now enable pipewire pipewire-pulse
pactl info
should show Server Name: PulseAudio (on PipeWire 1.0.0)
then just reboot and you're golden