Silksong starts very difficult compared to Hollow Knight, largely because there are many early foes that will deal 2 masks of damage. Those sorts of big attacks were generally reserved for mid to late bosses in Hollow Knight, and it caught even skilled players off guard. Hornet has a lot of mobility though, and a much easier time dodging out of the way, so once you adapt to her playstyle (be patient, dodge, and punish only when you know it's safe) the difficulty settles down and the game feels pretty fair.

As usual, you're gaining all sorts of tools and abilities along the way, and a few areas you can technically access early are best saved for later, when you have better gear. Some players aren't super thrilled with arena challenges, which this game has more of: suddenly 3-4 enemies in a small room all at once. I enjoy the meta challenge though: which tools can thin the crowd? Which minions should I focus to make the rest of the group manageable? If I can avoid taking damage, I can cast spells to thin the crowd much more effectively, etc etc.

With everything doing 2 points of damage, including environmental hazards, the player is at effectively 2.5 hitpoints for a large majority of Act 1, as opposed to 5 in Hollow Knight. This changes the feeling of the game from "oh, a challenge, let's see what will happen and I'll learn" to "shit, a new room, I don't want to explore because I'll just get killed, where was the last bench, can I even get back here?"

The other big difference, I think, is that Hollow Knight starts you out with a very straightforward downward attack that you can use as a pogo to mitigate a lot of damage/environmental hazards.

Hornet's 45º downwards attacks are significantly harder to aim/time, and pogo chains (where they are even possible) take a lot of practice