The audio hardware in the PC generally isn't involved at all with bluetooth devices

So if both outputs sound equally crappy, it souldn't be the problem of a specific output device.

In contrary to the first sentence (but anyway):
USB-audio-sticks are cheap and the linux-kernel has a universal driver buiild in. Can be worth a try.

Dell offers Ubuntu for some notebooks; maybe for testing purposes ... .

I thought that pipewire was the new requirement for Plasma?

Just my 2 cents here: I run happily Devuan 5 with KDE Plasma with pure ALSA. I had to tailor /etc/modprobe/alsa.conf to convince Plasma to use my prefered sound output. YMMV.

VLC can be handy to troubleshoot, because in it you can change sound output on the fly.

Then would be a bit better using older kernel versions (I saw changelog and it seems staying on 6.19 works I guess), and I'm also waiting for nvidia to update with backports for their drivers on Debian repos... I hope it's soon... the usual pain with nvidia

Agree!
I will try this trick at Stable Devuan
https://gist.github.com/Anakiev2/8d62e2 … ff855a22a7

This might be faster if the device is large. It should be enough to wipe out the partition table and let you start new.

1. Ceres\Sid still support nvidia 340 driver but Stable not
2. Ceres feels snappier then Stable at my old PC

As for other problem, as previous poster said, try adding the repository to sources list. Also check the:
   apt-cache policy
to see if there might be some pinning/priority related problem. Don't forget to run apt update after adding the repository to sources.list

firefox > out.txt 2>&1

Firefox outputs quite a lot. When it freezes, wait a bit. The output might be buffered, so give it a minute. You might examine out.txt while firefox is still running and also after you stop it.

X.

In fact there were two problems. The quirky one was about a pin on the hardware interface, related to speakers, not being activated.The problem is solved with help of ChatGPT, and, to be honest, I don't really understand how and why it works,because it is very much hardware related. The sound device I am using is:

Audio device: Advanced Micro Devices, Inc. [AMD] FCH Azalia Controller (rev 01)

It is Realtek chip, far as I can understand. Rather common sound hardware. It works fine with Slackware on the other partition. The solution which worked was to add the following to /etc/rc.local I have modified the script a bit

(
SDEV="/dev/snd/hwC0D0"
sleep 5 
if [ -e $SDEV ]
then
   hda-verb $SDEV 0x15 SET_PIN_WIDGET_CONTROL 0x40
else
   echo "$DEV not found"
fi 
alsactl restore
) & 

'hda-verb' line is the key. I wish I understand the problem better, but I don't. I hope it might help somebody else with similar issue. Also, I should say that Excalibur was installed from single 'server' CD image (around 650M).Perhaps the installation from some larger image solves the problem somehow.

The second problem is trivial compared to the first one. I have two sound device on the system. The other is HDMI device in the NVIDIA card. It works with speakers attached to the monitor, which I don't have.  So I blacklisted the device :

blacklist snd_hda_codec_hdmi

Also the initrd needs to be updated with update-initramfs. This second issue might be trivial, but till someone might lose hours getting around it.

Either way, the sound works now.