Sekiro, like Bloodborne, is different from the Dark Souls series. The mechanics, story, and atmosphere of each are distinct, with Elden Ring falling most closely with the Dark Soul series in mechanics and ‘feel’.

Dark Souls 1 has the best atmosphere and environmental storytelling, in my opinion. It really is clear how innovative and influential a game it was.

Sekiro is hard to play from a Dark Souls foundational playstyle. Sekiro players, I find, seem to have an easier time adapting to Dark Souls. So it may very well be a good start for a FromSoft game.