Uninstalling Pipewire is not an option for KDE. Only the systemd service can be turned off
Conversely, uninstalling all PulseAudio packages is required by pipewire-pulse
One of the packages included in metapackage manjaro-pipewire
pamac info manjaro-pipewire
Name : manjaro-pipewire
Version : 20210109-1
Description : Meta package for pipewire support.
URL : www.manjaro.org
Licences : GPL
Repository : community
Depends On : pipewire pipewire-alsa pipewire-pulse pipewire-jack
wireplumber
Packager : Stefano Capitani <stefano@manjaro.org>
Build Date : 09/01/21
Signatures : Yes
pamac info pipewire-pulse
Name : pipewire-pulse
Version : 1:0.3.23-1
Description : Low-latency audio/video router and processor -
PulseAudio replacement
URL : https://pipewire.org
Licences : LGPL
Repository : extra
Depends On : pipewire-media-session libpulse
Make Dependencies : git meson doxygen graphviz xmltoman valgrind libpulse
alsa-lib gst-plugins-base rtkit dbus sdl2 ncurses
libsndfile bluez-libs sbc libldac libopenaptx
libfdk-aac
Check Dependencies : desktop-file-utils
Provides : pulseaudio pulseaudio-bluetooth
Conflicts With : pulseaudio pulseaudio-bluetooth
Packager : Jan Alexander Steffens (heftig) <heftig@archlinux.org>
Build Date : 04/03/21
Signatures : Yes
You can see how installing manjaro-pipewire works out in these discussions
Failed update due to conflicting packages "pipewire-pulse" and "pulseaudio"
What is the correct way to install package “manjaro-pipewire”?