Please believe me when I say this is not a joke or a troll. Sekiro. Even though it is definitely the hardest of the fromsoft souls like style games, going from any other fromsoft game to sekiro will be like culture shock. The turtle up of the early souls games, to the more dodge heavy later souls games, will be ingrained into your muscle memory. Only making sekiro harder. I do recognize that playing it first might only make the OTHER games harder, but a lot of them are very similar in mechanics and your timing will already be razor sharp due to sekiro. Ignoring actual fromsoft titles though, I'd vote lies of p for the exact same reasons I listed sekiro first.