And if you really want notifications, they can still be enabled via the Google Chrome app when you visit the Facebook website.
Works good enough for me. I browser Facebook on the browser when needed (never) and use Messenger for chat alerts.
On desktop, I use http://messengerfordesktop.com/ to avoid going on the Facebook website.
I also use custom CSS on the Facebook website to break some of it's linearity. This make it less likely that I will browse mindlessly. Facebook UI is designed as a precise drug and simply changing it a little bit will disrupt that. (I use a red UI, a noisy background, bigger fonts, etc.)