https://guix.gnu.org/manual/en/html_node/Sound-Services.html
(define %my-services
;; My very own list of services.
(modify-services %desktop-services
(alsa-service-type config =>
(alsa-configuration
(inherit config)
(pulseaudio? #f)))))
reconfigure, reboot, login to gnome, then
bash-5.0$ pgrep pulseaudio
517
1261
