What is the ruling regarding one who commits major sins and enjoys some of them, and desires to repent but is unable, and feels their heart is hardened and their supplications are not answered?

Hating acts of disobedience is a sign of complete faith, and delighting in them contradicts the required complete faith, though it does not necessitate disbelief. Your delighting in acts of disobedience is a sin, and you must repent sincerely. To achieve this, you should remember the ugliness and harm of acts of disobedience, keep company with good people, frequently remember and supplicate to Allah, beware of thinking ill of Allah, frequently remember death, recite the Quran with humility and contemplation, strive to learn beneficial knowledge, and struggle against your soul to abandon and hate acts of disobedience.