"bug on bug ride and the bug rule"©

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.

the forumuser igorzwx has posted the most elegant solution have seen so far (been ubunt/debian user since ubuntu 12.04) -
it is not perfect , but function very well and steadfast; please it can become more universally adaptable with fall-back-mechanisms when more devices are used (a bit like on kde with phonon) (maybe this is already achievable, but just did not figure it out).

since have had to setup the devuan 6 once again lastly, have wrote down the adapted instructions posted here in the so called "manual".

for installing alsa devuan 6 maybe like this

sudo apt-mark manual libpulse0 libpulse-mainloop-glib0 libpulsedsp 

sudo apt-mark hold pulseaudio* pipewire* 

sudo apt-get purge wireplumber pipewire-alsa pipewire-audio pipewire pulseaudio pulseaudio-utils pavucontrol pulseaudio-module-bluetooth pipewire pipewire-bin pipewire-pulse

then you can configure .asoundrc after reboot or so, or use the tool "arateconf" which don't know if it already available in the repositories.

it can be installed via these instructions.
https://dev1galaxy.org/viewtopic.php?pid=57771

(just use under point "Install gcc-10 and g++-10 from Devuan's oldstable repositories." oldoldstable instead of oldstable

then you can use "arateconf" to create the .asoundrc and alsa will can function beautifully for you; as said, not perfect, but viable , and gentler to the ears.

IIRC in the past (Debian 7?) KDE required a different system. ALSA was always underneath everything, but it used to use something else. It escapes me at the moment. Pulse Audio! Just hit me.

Also, alsamixer responds that the host is down. Considering that this is audio and not a network, my guesses are that a service is down, possibly due to a missing kernel module.

EDIT -
I tried starting the alsa-utils service and it failed.

alsa-lib main.c:1554:(snd_use_case_mgr_open) error: failed to import hw:0 use case configuration -2

Something isn't happy.

Maybe try .asoundrc ?

This is the way!

The fix doesn't "stick," though, after a reboot. I'm sure there's a way to make it the default, some file to edit, probably. If anyone can suggest such an edit, I would be very grateful!

Problem is with a big DE like that not to mention pipewire, you might not get proper output from that command, but it's what i'd do first.