Another option is to type notifications into the search box in Windows, to find the Notification & Actions screen, there are six check marks, the bottom three need to come off to get rid of MS's nags about all sorts of things... so may as well take care of them while you're in there.
Then below in the Get Notifications from these senders section, find the browsers and flip them to off.
Sites can't send notifications if Windows says no!
It's a rather aggressive approach, but I've been considering it lately.