Its more about mentality than the attacking players not being defensive.
They were cruising vs Madrid, Messi was running the show, then Donnarumma made a howler and they shat the bed.
Second goal there was 6 PSG players in the box vs two from Real, Marquinhos defending was disgraceful.
Losing the third goal straight from their kick off had nothing to do with the front players either.
Also PSG fans are forgetting Mbappe is desperate to leave and go to Real.