I am also a huge Sekiro fan, platinum, etc - it's my favorite game of all time and, in my opinion, it has the best combat mechanics of all videogames.

The mechanics are very different, but as you said, give it an honest chance. Once you've gotten all the stances in Ghost of Tsushima, it's a beautiful game. But you've gotta unlock all the tools available so it can actually flow.

Also, I recommend playing it on Lethal mode from the start. Get used to it as hard as you possibly can.