PipeWire downmixing 7.1 audio on KDE neon, tried all standard config and pactl methods

Operating System: KDE neon User Edition KDE Plasma Version: 6.4.3 KDE Frameworks Version: 6.16.0 Qt Version: 6.9.1 Kernel Version: 6.16.0-061600-generic (64-bit) Graphics Platform: Wayland Processors: 6 × Intel® Core™ i5-9500 CPU @ 3.00GHz Audio Hardware: Intel® UHD Graphics 630 HDMI output to a Denon receiver Problem Description: My system has a working 7.1 audio setup, but it is incorrectly downmixing multi-channel audio sources to stereo. When I play a multi-channel audio file, only the front-left and front-right speakers produce sound. The speaker test in my sound settings works perfectly for all 7.1 channels, confirming the hardware and drivers are functioning correctly. A PipeWire graph screenshot from helvum showed that VLC was correctly outputting a 7.1 signal, which confirms the issue is a downmixing problem, not a problem with the source. Troubleshooting Steps Taken (with Outcomes): I have exhausted all standard and non-standard methods for enabling upmixing and preventing downmixing. Each attempt to modify a configuration file has led to a critical failure of the audio stack. The system has been restored to a working state after each failure. Attempted wireplumber policy edits: Action: I tried to change the ["audio.no-dsp"] value from false to true in /usr/share/wireplumber/policy.lua.d/10-default-policy.lua. Result: This caused the entire audio stack to fail. I had no sound, and the system reported "no input or output devices found." The system was restored by copying a backup of the original file. Attempted other configuration file edits: Action: I attempted to add upmixing rules to both pipewire.conf and 10-default-policy.lua. Result: Both attempts caused the respective services to crash with "Connection lost" or "no input or output devices found" errors. Used pactl commands: Action: I used pactl load-module to create virtual sinks with module-remap-sink and module-remap-channels. Result: The module-remap-sink command successfully created a sink, but the audio still did not upmix. The module-remap-channels command failed with a "No such entity" error. Attempted to switch to PulseAudio: Action: I tried to install the ubuntustudio-pulseaudio-config package to switch my audio backend. Result: The installation removed pipewire-alsa due to a dependency conflict, leaving the system with a broken audio setup. The system was restored by reinstalling the PipeWire stack. Final Conclusion and Call for Help: All troubleshooting paths lead to a critical failure of the audio stack when standard configuration changes are made. The issue is not with the configuration file syntax, but with a deeper logic problem that prevents the system from correctly handling the multi-channel audio. I am looking for a solution that can either: Address why standard configuration changes are causing critical failures on my system. Provide a reliable way to get a multi-channel audio source to play correctly without downmixing. Suggest a different, more stable method to switch from PipeWire to a working PulseAudio stack on KDE neon. Thanks Ysalmon... Ysalmon has my Solution @ https://askubuntu.com/posts/1528102/revisions