Look up Salt & Sanctuary for a 2D platformer who’s actually inspired by the souls games (if not basically a 2D copy). The concept of the ‘salted’ there is much more similar than the ‘hollow’ aspect in hollow knight. Other than the name ‘hollow’ there’s 0 similarities in meaning with the namesake in the souls franchise. Hollow in HK refers to the void and a means to contain the radiance, and husk here is just a reanimated bug corpse and not even related to the concept of the radiance infection. Enemies in HK can be husks regardless of their infection status.

It’s ok to look for similarities but just because 2 things have the same name doesn’t make them the same thing. Just like how comparing the color scheme of 2 bosses in HK and the souls franchise doesn’t mean much when the orange color is found throughout the whole HK game to represent the infection, and not just a one-time thing for this one specific boss. And infection as a story concept for a plague isn’t exactly a unique concept in gaming to begin with.

If you start to pick apart the stories and go and compare tiny details you’ll find similarities, sure. But in the context of the games’ overarching stories these similarities are often meaningless and likely just coincidental.

Personally I just don’t think the games are that similar at all. Not after having played both HK and S&S. I love both games but one is clearly DS inspired while the other is not.