OK.
I'm saying that even if they know about red flags they'll proceed anyway.
No plan survives contact with the enemy.
They'll make excuses to deal with the cognitive dissonance.
Trying to be real here.
I agree that as looks and charm fade, the options for covert narcissists shrink considerably.
These things tend to be a main weapon in their arsenal.
Their pool shrinks with their looks.
They'll go back to exes they cruelly dumped and if those exes are not in a good place, or have an ego themselves who won't allow them back in, they'll fall victim again.
They also lack the outgoing nature of the 'classic' narcissist which means less people around them.
I know of one. Long-term unemployed guy, living in an old people's complex, only in mid-fifties, daughter doesn't speak to him, former cocklodger whose ex kicked him out about the same time most women become menopausal.
His looks are fading fast, the boyish charm he had at 30 now looks weird on a man in his fifties.
I imagine that in his twenties the arrogance was accepted as he had potential it honestly seems pathetic now that that potential has not been realised.
OP's ex sounds like a classic narcissist though. In my experience, they do tend to be successful for a lot longer, sadly.
There's a more positive, can do attitude to them.
They tend to work harder, too.