OK I figured it out…
Seems like Manjaro’s relevant default options in /usr/share/alsa/alsa.conf are the following:
defaults.namehint.showall off
defaults.namehint.extended off
To override this behavior, I just created the ~/.asoundrc file with the following lines:
defaults.namehint.showall on
defaults.namehint.extended on
Now I have the same output from aplay -L on Manjaro as on Raspberry Pi OS.
Hope this is useful for someone.
Cheers!