I’m going to try to restate the OP question in my own words.
It’s all about wanting to view and act upon notifications which have already been cleared, either by accident or whatnot.
In my case, I tapped on a notification from the Email app, and then the app for some reason failed to actually open that particular mail. Searching in the app has not found the mail.
So to me, if I could get that notification back, even though I cleared it, this may be a path to get to read that email.
There are other situations when I would have liked to see old notifications that were already cleared.
So that is the OP question as I understand it. None of the snarky answers (lookin’ at you, “bit bucket”) seem to have grasped the actual question.