Title says pretty much everything.
I checked, and I have all the lib32 packages for libcanberra, including the -gstreamer and -pulse packages, same with the 64-bit packages.
There’s only one package for xapp in the Arch repository, and I have it installed.
I considered I need lxappearance for xapp, but I already have lxappearance-gtk3 as part of Customize Look and Feel. I uninstalled CLaF and installed lxappearance anyways just to check, and it didn’t work.
What do, flathub?
EDIT: Here’s the output.
[andyr@andydesktop flatpaks]$ flatpak run --share=ipc org.gnu.emacs
emacs-wrapper-wrapper: Setting up NPM packages
emacs-wrapper-wrapper: Setting up Cargo packages
emacs-wrapper-wrapper: Setting up Python packages
Gtk-Message: 23:00:39.159: Failed to load module “xapp-gtk3-module”
Gtk-Message: 23:00:39.159: Failed to load module “canberra-gtk-module”
Undefined color: “WINDOW_FOREGROUND”
2ndEDIT: I at first used “flatpak run org.gnu.emacs” but changed it to “flatpak run --share=ipc org.gnu.emacs” after seeing that proposed solution in an answer to someone else who had a similar problem on Zorin OS.