It doesn't matter what you set any of these things to, if you leave your account idle for a while you'll start getting made up notifications again to try to draw you back in. Both Facebook and Twitter do this, though ime Facebook's tend to work better just because I have marginally more reason to care about any given person on my FB feed than the much more eclectic set of people my Twitter is connected to.

Strange, I've never seen a Facebook or twitter notification. They both have notifications switched off and android respects that.

My twitter account goes weeks without being accessed.

Lots of companies dump all notifications into the same bucket, either out of laziness, or purposefully to make it less likely you turn off their spam notifications (looking at you Oculus).

Facebook only appeared to divide notification into categories when its data misuse unfolds. Several years ago (if I recall correctly), turning off one broad category will indeed nuke the "nagging" notification, but also turn off legitimate ones as well.