Out of all the games in the Miyazaki series I feel like Sekiro doesn’t get enough love. It’s hard to say whether I love the gameplay or the world/lore more because I’d never seen a what is essentially a cosmic horror take on Buddhism before and that just scratched an itch that I never knew I had
The problem with Sekiro is that the combat focuses on one particular thing, and its not an RPG, so if you are bad at that thing, the game is basically unplayable.
I'm stuck on the (apparently optional) castle nightmare/flashback part, but I agree. Sekiro's combat is a fluid puzzle without relying too much on sword and weapon placement like others do (For Honor, Blade Symphony, etc; but I still appreciate what these games are trying to do).
The section with the burning buildings and the big guy in the middle of the court yard just past the shallow water?
If that's the section you mean, then you can safely come back after progressing the main line a little more. Getting the axe and the beating the guy on the horse are good pre-requisites. That will align the difficulty to be more consistent with the main line path.