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
You can always take it later on whenever you feel like - I've lasted until the Roof Dad
But it does change the game in a fundamental way, beyond the usual "enemies will have more HP" of the DS3 new game+.