For notifications to work, you have to install Google Services Framework, Google Play Services, and Google Play Store. Just installing GSF isn't enough.
Also, if you installed these three apps after other apps, notifications won't work. You need to install the Google apps first.
cleanclosedcoffee Also in my secondary profile GSF took over 500mb of Space which also appears to be unsusual.
Maybe. Mine takes up around 20 MB. Since your notifications are already broken maybe clear the app's data at Settings > Apps > All apps > Google Services Framework > Storage & cache > Clear storage.