I’m not sure spotifyd is just spotify (Edit: I checked, its some kind of spotify client meant to be run as a daemon? No idea what permissions that needs)
And the user that executes a service isn’t determined by who owns the service file, there is a user option in the service config
Boot from a live disc/usb, check the kernel logs. That should at least tell you where the boot process got stuck, what to do about it depends on what exactly broke.