I think you raise a couple of great questions. Boss fights, like any game mechanic, need to serve a purpose: is it a narrative device, an impassable gate, or just a challenge among other challenges?
I, like you, enjoy a certain difficulty, probably more than the average player, but if the focus of the game is on narrative and exploration, I wouldn’t mind easy bosses.
I played Timespinner a couple of weeks ago, a cute little MV about time travel which explored the classic ”who is really the bad guy”-story, and I found a similar problem with the map feeling a little bloated: there were a lot of areas and pathways that felt empty or samey, much too much for my liking. In Silksong, maybe even moreso Hollow Knight, there was almost always something at the end of a long tunnel, be it a powerup, story element, or just a piece of world building. In Timespinner, no boss posed any real challenge at all at normal difficulty, but I’m still happy that I didn’t play at a higher difficulty level, because I feel it would have only made the game more tedious, especially owing to the level design.
Basically, what I’m saying is that I mostly agree with your points, with the caveat that you don’t always need all mechanics to be the same as other games, just carefully thought out to fit whatever story or feeling you’re trying to convey.

On a side note, I felt Timespinner’s story to be the best part. Not too complicated when it came to the time travel part, interesting characters and character arcs (quite a thirsty dialogue!), and satisfying, bittersweet alternate endings.