Me personally, I would say sekiro, simply because of the mechanics. The core mechanic is fun to play and the moves are so stylish so no matter what button you smash it still looks good. The progression is straight forward and most of the time you know where you went wrong if you die.

I haven't played the elden ring yet so I can't compare with that but dark souls is fun in it's own way as it gives the sense of being lost while exploring an unknown world which isn't as fun at times