I was exactly the same, could not put it down until I got my platinum and all the boss gauntlets.
Make sure to try "charmless" mode - it's the way Sekiro was meant to be played. On your second/third etc playthrough Kuro will ask you if you want to take his charm (in the first playthrough he just gives it, no question asked), say "no" and enjoy
![Smile :) :)](/styles/default/xenforo/vbSmilies/Normal/smile.gif)
You can always take it later on whenever you feel like - I've lasted until the Roof Dad
![Smile :) :)](/styles/default/xenforo/vbSmilies/Normal/smile.gif)
But it does change the game in a fundamental way, beyond the usual "enemies will have more HP" of the DS3 new game+.