I absolutely adored Hollow Knight, but my favourite platformer gotta be Celeste. In no small part due to its accessibility, but also great character writing, organic learning curve and gorgeous soundtrack!
On a more replayable side, my most played platformer is Dead Cells - which is understandable, since it is a roguelike.
Overall, in a platformer game I value learning curve and ease of controls more, since I’m not very good at this genre (as opposed to soulslikes, where I usually welcome the challenge). But of course, a good story transcends genres.
Even C levels felt fair to me. The only level I genuinely got frustrated with is the final final chapter, as it relies on some advanced platforming tricks I can’t perform consistently. But then again, it is basically a free DLC for the game so I understand the difficulty spike