Stuck troubleshooting ALSA and pipewire on Debian 13 (Trixie) - "Host is Down"; pipewire likely not running

After reinstalling parts of my audio environment in an effort to sort out conflicts between pulseaudio and pipewire, I am trying to get the audio environment on my debian 13 box running again.

Currently,

• pulseaudio is not installed

• pipewire is installed, with recommended additional packages like pipewire-pulse or pipewire-alsa

• alsa seems to be installed with recommended additional packages

What works:

• I am able to capture (record) audio from the mainboard's line in using audacity.

• I am able to play a file using audacity to the PC's built in speaker

As this is about it, I assume that the only thing still available is direct communication between hardware (with kernel drivers) and software capable of talking to the drivers directly - i.e. without intermediate layers like ALSA or pipewire, not very handy for everyday use and leaving everyday requirements like playback from browsers or media players unavailable.

Also, the sound hardware and driver seems to be reported correctly:

... and ALSA seems to be up to date.

What doesn't work:

Alsa appears to be unavailable, as reported by error messages in playback applications like VLC or audacious or by aplay as found in this checklist.

I get the same when I try to launch alsamixer (which has worked beforeTM)

Pipewire seems to miss configuration data and modules, or does not start automatically after booting (edited later).

When run as root (edit):

When run as user (edit):

(I remember to have gotten a similar output also when trying to run as root)

No abstraction layer of any audio interface appears to be accessible; in the settings of audacious, I get error messages:

• Output Plugin "Pipewire Output" -> Error opening output stream

• Output Plugin "ALSA Output" -> "ALSA error: snd_pcm_open failed: Host is down."

• etc.

Also, # alsa-info tells me that ALSA is probably up and running, but PipeWire is not, thus there is no sound server on the system. In alsa-info's output file, I read this:

This might also be a hint: Launching $ pavucontrol opens the app, and it starts telling me it is "Establishing conncetion to PulseAudio. Please wait...", and fails to do anything else. This could mean that PulseAudio was not cleanly replaced by pipewire, or pipewire-pulse might be there to replace PulseAudio, but is not running or cannot be found.

This is where I am currently stuck.

The stupid solution would probably be to do a fresh installation of the system, hoping that configurations or dependencies will magically be fixed. However, I would like to understand the problem, ideally using the approach of a troubleshooting tree or checklist, because I assume that drivers are present and alsa remains unresponsive because it fails to communicate to them or pipewire is unaccessible or has taken the role of alsa, but will not be addressed properly by audio applications.