That was the feeling I got when I started. I've played DS3 and its DLCs for over 200 hours, Bloodborne and its DLCs for 170, and Nioh for 150. I've also beaten DS1 and DS2 as well. This game might look like all of them, Nioh included, but Sekiro just seems like From knew they could get Soulsborne/Nioh fans to try to get their fix.
In Sekiro, the fighting system does kind of seem like its hard just to be hard, but unlike Soulsborne/Nioh, it's hard to learn from your deaths (and thus be able to use the lessons). Additionally, the level up system is rather burdensome; there is no leveling up stats, just a skill tree. Would be nice, except many of the skills you learn cannot be used with each other. You have one sword move and one sword. Contrast to Soulsborne/Nioh with tons of weapons. The visuals look nice, but if you've played Nioh, the environments feel like underwhelming. Plus, the protagonist looks like both Geralt of Rivia and William (from Nioh).
Not a bad game, but this strikes me as just a way to tell From fans that they're not forgotten about as we await Bloodborne 2, as well as to try to hurt Nioh 2's sales.