In the current Mountain and Sea Realm, the pinnacle of the Immortal Realm was the Paragon. After opening 123 Immortal meridians and forming 33 Heavens, one could step into that ultimate Realm of Immortality. That was the highest place in the modern age.
Meng Hao was the only one who had currently reached that level, surpassing the achievements of the most powerful of the Mountain and Sea Lords, Ksitigarbha of the Fourth Mountain and Sea.
Perhaps with the assistance of various techniques and divine abilities, future powerhouses might be able to brush against this kind of power. But Meng Hao had reached Immortality by corroborating the Dao on his own. That was a higher level that no one could match!