Hollow Knight can get very, very frustrating. So if you were to play it through in order to allow yourself to play Silksong, you might just end up throwing the towel.
Silksong is very hard too, but I feel like you get new abilities sooner and more often, the story is easier to follow, and also you’d be playing it at the same time as everyone else, it’s nice.
But maybe the hours I’ve put into Hollow Knight are affecting my appraisal of the new game.