Sometimes the impersonalists accept Kṛṣṇa as Bhagavān, or they accept His authority. Yet many liberated persons cannot understand Kṛṣṇa as Puruṣottama, the Supreme Person. Therefore Arjuna addresses Him as Puruṣottama. Yet one still may not understand that Kṛṣṇa is the father of all living entities. Therefore Arjuna addresses Him as Bhūta-bhāvana. And if one comes to know Him as the father of all the living entities, still one may not know Him as the supreme controller; therefore He is addressed here as Bhūteśa, the supreme controller of everyone. And even if one knows Kṛṣṇa as the supreme controller of all living entities, still one may not know that He is the origin of all the demigods; therefore He is addressed herein as Devadeva, the worshipful God of all demigods. And even if one knows Him as the worshipful God of all demigods, one may not know that He is the supreme proprietor of everything; therefore He is addressed as Jagatpati. Thus the truth about Kṛṣṇa is established in this verse by the realization of Arjuna, and we should follow in the footsteps of Arjuna to understand Kṛṣṇa as He is.
Bhagavad-Gita------10:15------purport).

The Supreme Personality of Godhead, Viṣṇu, resides within the material world as the sattva-guṇa-avatāra. Lord Śiva is the tamo-guṇa-avatāra, and Lord Brahmā is the rajo-guṇa-avatāra, but although Lord Viṣṇu is among them, He is not in the same category. Lord Viṣṇu is deva-deva, the chief of all the demigods.
( Srimad Bhagavatam------8:12:4------purport).

No one is equal to or greater than the Supreme Personality of Godhead, and therefore He is described here by many words: jagannātha, deva-deva, vṛṣākapi and puruṣa. The supremacy of Lord Viṣṇu is also confirmed in Bhagavad-gītā (B.G.10:12) in this statement by Arjuna:
paraṁ brahma paraṁ dhāma
pavitraṁ paramaṁ bhavān
puruṣaṁ śāśvataṁ divyam
ādi-devam ajaṁ vibhum
"You are the Supreme Brahman, the ultimate, the supreme abode and purifier, the Absolute Truth and the eternal divine person. You are the primal God, transcendental and original, and You are the unborn and all-pervading beauty." Kṛṣṇa is ādi-puruṣa, the original Personality of Godhead (govindam ādi-puruṣaṁ tam ahaṁ bhajāmi). Viṣṇu is a plenary expansion of Lord Kṛṣṇa, and all the viṣṇu-tattvas are parameśvara, deva-deva.
( Srimad Bhagavatam------10:1:20------purport).