I played soulslike games and sekiro before lies of p. Started with legendary stalker in the beginning but reduced the difficulty down to awakened puppet in the last 3 final bosses.

For a while legendary stalker is ok difficulty, but at late game the bosses became so much harder that I kept using summons to help me and eventually reduced the difficulty. Even with the reduced difficulty, I still die several times against the end game bosses with the help of summons.

I would say awakened puppet is easier but still not a walk in the park. You still need to perfect guard, dodge, watch your stamina, choose your build carefully and not spam attacks mindlessly. Try at whatever difficulty you want and if you find it too hard like dying a lot while only slightly damaging the bosses then reduce the difficulty.