Loved all the souls games. Sekiro has the best best combat by far, its amazing. Its an example of From focusing on a more singular idea for combat, but that is also the weakness. I prefer the demon/dark souls more for build diversity and playstyles options. Sekiro does have some choices in tools but they really want you to play a certain way.
Sekrio has some of my favorite boss battles in terms of just combat, owl version 2, Genichiro, and the last boss are insanely good. I remember getting to the Genichiro and thinking are they fucking nuts this is impossible?!! Then that fight literally teaches you how to play the real game, loved it. I totally get why some might dislike it, the combat demands more than demon/darks souls due to the necessity to parry and counter.
Overall though the dark souls series wins for me due to its dark horror themes and various build/play styles.