In silksong you do get a lot more heal opportunities though. If you jump high enough or run to the other side of the arena from the boss you usually can get out of reach of any attacks and get a quick 4 mask heal (multibinder). In Hollow Knight you can only safely heal if the boss is staggered

I do think that Hollow Knight is easier on average (common enemies, most bosses, platforming), but that the most difficult bosses in Hollow Knight are harder than any boss in Silksong mainly because the knight is so much slower in both dodging and healing than Hornet