Can someone who does not pray, disobeys their parents, and commits sins be a lover of the Messenger (peace and blessings of Allah be upon him), and what is the ruling regarding those who differ on this matter?

It is permissible for the love of Allah and His Messenger to coexist in the heart of a disobedient person. The proof for this is the hadith about the drinker of alcohol, in which the Prophet, peace and blessings be upon him, said: "By Allah, I know nothing but that he loves Allah and His Messenger." However, persistence in sins can lead to the heart being sealed and this love being removed. Ibn Hajar mentioned that the negation of faith from the drinker of alcohol does not mean its complete removal, but rather the negation of its perfection. It is also possible that the affirmation of the love of Allah and His Messenger in the heart of a disobedient person is conditional upon his repentance and the implementation of the prescribed punishment upon him. Otherwise, there is a fear for him that, with the repetition of the sin, his heart may be sealed and that love removed from him.