Davinci Resolve no Audio

After a succesfull Install of Davinci Resolve 17 through yay (AUR auto-installer) everything seemes to be working fine (after an install of the official NVIDIA GPU Drivers), except the audio. Here is an example video:


The Audio used in this clip is 2SCOOPS - Donuts from NoCopyrighSounds.

The Log shows this error many times:

ALSA lib confmisc.c:165:(snd_config_get_card) Cannot get card index for Loopback

By the way: VLC Media Player shows an error with ALSA when it’s trying to use the audio device “default”:

Audioausgabe fehlgeschlagen:
Das Audiogerät “default” konnte nicht benutzt werden:
Kein passendes Gerät gefunden.

That just means:

Audio Output failed:
The Audio Device “default” could not be used:
No matching Device found.

Maybe that’s the problem?

I already trid to edit /etc/asound.conf to select a default audio device, with no luck.
And something like this post didn’t help me: