There is, actually! It's available as a Guix Home service: home-pipewire-service-type was introduced around the end of December, and you can see documentation for setting it up in the manual.
When using this service, pipewire-pulse is used by default without any extra configuration.
I think I came across this, but from my understanding, this is a Guix Home services, right? And not the one suitable for system configuration?
I've never tried putting it in the system configuration, but I imagine it wouldn't work as it depends on Guix Home services.
If you haven't used Guix Home before, the home-environment record doesn't have required fields like operating-system does so it's fairly easy to get started with.
Here's a minimal working configuration, for example:
(use-modules (gnu)
(gnu home services desktop)
(gnu home services sound))
(home-environment
(services
(list (service home-dbus-service-type) ;home-pipewire-service-type needs this
(service home-pipewire-service-type))))
I should have asked this before, but I also want to ensure that the default PulseAudio is disabled. How can I ensure that? Would this work with GNOME Shell properly?
I haven't found a need to do it, but a (modify-services ... (delete pulseaudio-service-type)) in your operating-system declaration might do what you're asking? I don't think this is necessary though. As far as I'm aware, applications that attempt to use Pulseaudio will be transparently rerouted through pipewire-pulse, which is already configured by home-pipewire-service-type. I am also on GNOME, and I haven't noticed any breakage in this aspect using it.
If you're unsure that it works the way you want, you can always try the configuration out and see how it goes (note that I had to re-log in for the wireplumber service to start properly).
Guix is an advanced distribution of the GNU operating system developed by the GNU Project