I liked Silksong a lot, but I do think Hollow Knight is a better game. I'm not sure I see what you mean are mistakes as much as design choices, but I do think there are several design choices in Silksong that are simply bad and were NOT made in Hollow Knight, which makes them all the more baffling.
I think the heights of Silksong are equally high to Hollow Knight, but the overall experience is not. There's a lot of needless frustration for no good reason and the average experience isn't to the same height (there are a few music tracks that are at the same level as Hollow Knight in Silksong, but in Hollow Knight it's almost every track, whereas Silksong has a majority that are just "good", not "amazing").
I still think that Silksong is a very, very good game and I think it's absurdly worth it for the price point it costs. But Hollow Knight was a better game in almost every regard, to me. The only area where I think Silksong cleanly beats Hollow Knight is movement. Moving around as Hornet feels amazing, though this isn't the case at the start of the game, only later on.
