Sekiro is possibly my favorite game of all time, and for sure my favorite From Software game. I can't even describe how much I love this game.
The feeling you get when you finally beat a boss that initially seemed literally impossible (looking at you Sword Saint Isshin) is incomparable. Just the biggest dopamine rush ever.
And it's like riding a bike. Once you get it, that muscle memory stays. I went a year or so without playing it, and within 5 or 10 minutes I was right back where I was.
Truly a gaming masterpiece. Enjoy it. Also, if you find yourself getting stuck on a boss and you find yourself getting into a loop of doing the wrong thing over and over, try giving it a rest for a bit and come back with fresh eyes.
I was struggling on the final boss for hours until I rage quit and went to bed. Tried again next morning and literally beat him on my second try.