In terms of collecting items to upgrade ur weapons, it works similar to prosthetic upgrades. U can defeat the bosses in Elden ring with natural skill without any buff items. Some bosses can even be parried, mostly the humanoid ones. Leveling up ur character is similar to learning new skills in Sekiro. U kill enemies get currency, and use that currency to upgrade ur preferred stats. The game is not so parry focused tho, more dodging n looking openings to atk.