“Enlightenment” is supposedly the essence of Buddhism. That is what it is for. But what is enlightenment?
Traditional Buddhism contains many different, contradictory theories of the nature of enlightenment. Modern Buddhism contains several additional new theories, based more in Western religion than Buddhist tradition.
Rather than taking these as alternative theories of a single thing—what enlightenment really means!—it’s better to understand them as different ideas about what would be the most desirable thing possible. They are wish-fulfillment fantasies; and as people’s wishes and fantasies differ, stories about “enlightenment” differ.
Rather than arguing about the true meaning or nature of enlightenment, it’s better to ask what goals you have for Buddhist practice, and whether those are realistically achievable.