Ya, Hollow Knight's first areas like forgotten crossroads and greenpath were a lot easier. There werent any mechanics you have to worry about other than jumping and attacking, and most enemies you faced just walk slowly towards you. Bosses were also fairly straightforward.

Compared to what areas in Silksong? Because Moss grotto and Marrow seem to have roughly the same range (and difficulty) of enemies as forgotten crossroads and greenpath. I think you also have somewhat rose tinted glasses regarding the starting areas of Hollow Knight because most enemies weren't walking slowly towards you. I'd say it was more of a 50/50 split between walking enemies and flying enemies with some flying enemies shooting projectiles and flying projectile shooters are much harder than the one projectile spitting regular enemy in the first 2 areas of Silksong.

By comparison Silksong has you fighting tougher enemies that could deal 2x damage, and quick bosses right off the bat like Bell Beast which kills you in 3 hits. Healing taking your entire bar also makes platforming more difficult because newbies will often be low HP and not have enough silk to heal.

I think the comparison here isn't as one to one with Hollow Knight. Silksong is much faster paced. Hornet is more mobile and heals faster (and heals more at once), so bosses killing in 3 hits might not be that much harder because it's easier evade attacks and healing is faster. Bosses killing in 5 hits in Hollow Knight might end up being harder than Silksong because healing is a much slower and deliberate action and you might not get a time to heal with an unfamiliar boss.

From my experience grotto and marrow have been comparable to crossroad and greepath. It gets harder after marrow but Hollow Knight also got harder when you got into fungal wastes. Maybe the pace change makes you feel like it's harder than Hollow knight but so far I haven't felt like it was noticeably harder than my first Hollow knight playthrough.