Mario games have been very backloaded with the “tough stuff” for a long time now. I think the idea is that your standard player is not put off by difficult platforming and plays through to the “end” of the game, enjoys the story, doesn’t die all the time, and basically has a very good time. For those of us with some skill, that’s when the game really gets good.
I have 144 moons and I’m at the Snow Kingdom having just “completed” the Seaside Kingdom. I have had a ton of fun in each one even though I haven’t been tested much to this point. I kind of disagree on the bosses too as I’ve found them to be inventive and enjoyable even when they’re not difficult, specifically the Broodal. They remind me more of the mid-level bosses in prior games.
I absolutely adored the New Donk City bit during the concert. This game makes me smile. :)