Not clear if this is the same issue, OP had no issue playing video, just had to change sound-backend, then set it back to get sound (no answer if correcting not having both pipewire & pulseaudio active fixes the issue), so make sure to clarify, and post all the logs as done in the first post.

See the first post in this thread and https://kaosx.us/docs.
But please start a new topic if you have no video loading at all, and no way to get sound working, even after switching as explained in the first post. Then your issue is not related to this thread.

If you have video loading (still no answer to that), but no sound, then it could be the same issue, since you also have set to activate both pulseaudio & pipewire. This cannot be resolved by KaOS, that is a a setting you need to correct on your system.
And the same counts as for the OP, on a rolling system packages are removed/replaced over the years,it is important to keep your system clean from complete obsolete/unmaintained packages (see your log, starting at line 242).
https://kaosx.us/docs/pacman/#list-installed-packages-that-are-not-in-the-official-repositories

its maybe kde error - i have to switch bitween analog dupleks stereo and analog stereo output every login. Now i know how it be resolved. But is annoying to go to the kde sound settings and switch the te right output.

My youtube video (audio and video of a youtube piece and all os sound related things) do not start until I make use of the workaround. And the workaround does not last, I have to do it again and again in a session.

And again, did you adjust to run only one sound server? For both of you, I have asked many times now, you need to adjust your system to either use pipewire or pulseaudio. Those are user determined settings, not set by Plasma or KaOS. For KaOS, pipewire is default (during first install) and disabling pulseaudio, but that can ONLY be set as default during a first install, after that, it is a user choice.

How can I delete/deactivate my pulseaudio sound server? I never adjusted or changed anything of the standard sound configuration. My system must/could have done this on its own.

Best first check how you're system runs audio:
first: pactl info it will tell you how pulseaudio is used (through pipewire or not)
next, check user activated audio:
systemctl --user status wireplumber
systemctl --user status pipewire
systemctl --user status pulseaudio
Then see if pulseaudio runs system-wide:
sudo systemctl status pulseaudio

Thank you very much for your help.

pactl info

Server-Zeichenkette: /run/user/1000/pulse/native
Bibliotheks-Protokollversion: 35
Server-Protokollversion: 35
ist lokal: ja
Client-Index: 6
Tile-Größe: 65472
Name des Benutzers: helmchen
Rechnername: helmchenLaptop
Name des Servers: pulseaudio
Version des Servers: 17.0
Standard-Abtastwert-Angabe: s16le 2ch 44100Hz
Standard-Kanal-Zuordnung: front-left,front-right
Standard-Ziel: alsa_output.pci-0000_00_1f.3.analog-stereo
Standard-Quelle: alsa_output.pci-0000_00_1f.3.analog-stereo.monitor
Cookie: d68b:731b

systemctl --user status wireplumber


● wireplumber.service - Multimedia Service Session Manager
     Loaded: loaded (/usr/lib/systemd/user/wireplumber.service; enabled; preset: enabled)
     Active: active (running) since Tue 2024-09-24 15:37:44 CEST; 9min ago
   Main PID: 854 (wireplumber)
     CGroup: /user.slice/user-1000.slice/user@1000.service/session.slice/wireplumber.service
             └─854 /usr/bin/wireplumber

Sep 24 15:37:44 helmchenLaptop systemd[758]: Started Multimedia Service Session Manager.
Sep 24 15:37:45 helmchenLaptop wireplumber[854]: wp-internal-comp-loader: Loading profile 'main'
Sep 24 15:37:45 helmchenLaptop wireplumber[854]: spa.bluez5: BlueZ system service is not available
Sep 24 15:37:45 helmchenLaptop wireplumber[854]: wp-device: SPA handle 'api.libcamera.enum.manager' could not be loaded; is it installed?
Sep 24 15:37:45 helmchenLaptop wireplumber[854]: s-monitors-libcamera: PipeWire's libcamera SPA plugin is missing or broken. Some camera types may not be supported.
Sep 24 15:37:46 helmchenLaptop wireplumber[854]: GLib-GIO: Unexpected reply 3 when releasing name org.freedesktop.ReserveDevice1.Audio0
Sep 24 15:37:46 helmchenLaptop wireplumber[854]: spa.bluez5.native: RegisterProfile() failed: org.bluez.Error.NotPermitted

systemctl --user status pipewire

● pipewire.service - PipeWire Multimedia Service
     Loaded: loaded (/usr/lib/systemd/user/pipewire.service; disabled; preset: enabled)
     Active: active (running) since Tue 2024-09-24 15:37:44 CEST; 11min ago
TriggeredBy: ● pipewire.socket
   Main PID: 853 (pipewire)
     CGroup: /user.slice/user-1000.slice/user@1000.service/session.slice/pipewire.service
             └─853 /usr/bin/pipewire

Sep 24 15:37:44 helmchenLaptop systemd[758]: Started PipeWire Multimedia Service.
Sep 24 15:37:46 helmchenLaptop pipewire[853]: spa.alsa: 'front:0': playback open failed: Das Gerät oder die Ressource ist belegt
Sep 24 15:37:46 helmchenLaptop pipewire[853]: mod.adapter: 0x55be5a85e700: can't get format: Das Gerät oder die Ressource ist belegt

systemctl --user status pulseaudio

○ pulseaudio.service - Sound Service
     Loaded: loaded (/usr/lib/systemd/user/pulseaudio.service; disabled; preset: enabled)
     Active: inactive (dead)
TriggeredBy: ○ pulseaudio.socket

sudo systemctl status pulseaudio 

Passwort: 
Unit pulseaudio.service could not be found.

I can't make heads or tails of all these data. Constantius24, do you know how to proceed?

I'm not an expert on this put it looks like both pipewire and pulseaudio are b0rked.
Your 'pactl info' results doesn't show what pulseaudio is running on. Mine has:
'Server Name: PulseAudio (on PipeWire 1.2.3)'

The output of your 'systemctl --user status pipewire' has on the second line pipewire.service disabled. Mine has:
'Loaded: loaded (/usr/lib/systemd/user/pipewire.service; enabled; preset: enabled)'

My suggestion would be that you reconfigure your sound to use pipewire exclusively.

pactl outcome shows pulseaudio is in use, but wireplumber is running.
So make a decision, do you want to stick with pulseaudio? then run:

systemctl --global disable pipewire
systemctl --global disable pipewire-pulse
systemctl --global disable wireplumber

The first 2 are probably not needed, looks like you only have wireplumber enabled, not pipewire.

If you want to move to pipewire (which was not available as install option when you installed KaOS in 2021), make sure all the above are set to enabled.

systemctl --user enable pipewire
systemctl --user enable pipewire-pulse
systemctl --user enable wireplumber

After reboot, pactl should show running on pipewire only (enabling pipewire will disable pulseaudio in normal installs).

Excellent. It is running. Thank you very much!