I know this question is about Puranas but it's stating a issue which is larger in scale. The sentence.:
"To show that golok niwasi shri krishna is the only bhagwan not any one else."
So, my views are as follows.:
“Bhagawan” is not an ordinary designation. As ISKCON Acharyas have translated the word “Bhagawan” as “Supreme Personality of Godhead”, which in simple language is nothing but the “Supreme Lord” above whom there is no one.
This attribute belongs only to Bhagawan Rudra because he is the Purusha, he is the Parabrahman as per Vedas.
“purusho vai rudrah |” (Taittiriya Aranyaka 10:24:1).
“Lord Rudra is the Purusha of Vedas”.
Shruti clearly calls Rudra as the bhagwan (boss) of all devas (gods), who created all gods and gave them their respective powers, positions and designations. Shruti denies the existence of any other bhagwan (boss) who controls Rudra who is the Veda Purusha himself.
Atharvasiras Upanishad clearly states that Lord Shiva is supreme. It says that nothing in past neither was ever greater than him nor can ever be in future.
“yasminnida.n sarvamotaprota.n tasmAdanyanna para.n ki~nchanAsti |
na tasmAtpUrva.n na para.n tadasti na bhUta.n nota bhavya.n yadAsIt.h |” (Atharvasiras Upanishad 5:05).
“There is none greater than him, on whom all the worlds are strung like beads. Over ages, nothing so far in the past was ever greater than him and nothing is going to be greater than him in future”.
Svetaswatara Upanishad also voices similar thoughts as shown below.
“na tasya kaarya.n karaNa.n cha vidyate na tatsamashchaabhyadhikashcha dR^ishyate |
paraasya shaktirvividhaiva shruuyate svaabhaavikii GYaanabalakriyaa cha |” (Svetaswatara Upanishad 6:08).
“There is no effect and no cause known of him, no one is seen like unto him or better; his high power is revealed as manifold, as inherent, acting as force and knowledge”.
“na tasya kashchit.h patirasti loke na cheshitaa naiva cha tasya liN^gam.h |
sa kaaraNa.n karaNaadhipaadhipo na chaasya kashchijjanitaa na chaadhipaH |”(Svetaswatara Upanishad 6:09).
“There is no master of his in the world, no ruler of his, not even a sign of him. He is the cause, the lord of the lords of the organs, and there is of him neither parent nor lord”.
So, it’s clear from above verses that there is nothing superior to Lord Rudra. He is the Supreme personality of Godhead. Now we’ll see in below verse that it is lord Rudra alone who created all Gods and blessed them with their positions and designations.
“yo devaanaaM prabhavashchodbhavashcha vishvaadhipo rudro maharshhiH |
hiraNyagarbha.n janayaamaasa puurva.n sa no buddhyaa shubhayaa sa.nyunaktu” (Sve Upa. 3:4).
“He, the omniscient Rudra, the creator of the gods and the bestower of their powers, the support of the universe, He who, in the beginning, gave birth to Hiranyagarbha—may He endow us with clear intellect!”
“sa hi kṣayeṇa kṣamyasya janmanaḥ sāmrājyena divyasya cetati |
avannavantīrupa no duraścarānamīvo rudra jāsu no bhava ||” (Rig Veda 7:46:2).
“He (Rudra) through his lordship rules on beings of the earth, on heavenly beings (gods) through his high imperial sway (controlling influence or power). Come willingly to our doors that gladly welcome thee, and heal all sickness, Rudra. in our families”.
Well, an interesting FACT related to the word “Bhagawan” is that Vedas hailed ONLY Lord Shiva with the title -“Bhagawan”.Yes, Vedas have not used the title called “Bhagawan” for any other god including Lord Vishnu, Lord Brahma and not even for Lord IND a also. They have used that designation exclusively only for Lord Rudra. Sri Rudram hymn from Yajurveda begins with the salutations to Rudra as the Bhagawan of Vedas. It says, “Om namo bhagawate rudraya |”, which means, “Salutations to lord Rudra who is the Bhagawan (Supreme personality of godhead)”. All other gods who received title as ‘Bhagawan’ received that title from Puranas not from Vedas. In fact in later texts (puranas), even Narada, Vyasa also got referred with that title, hence it became very colloquially used title for everyone in later texts. Bhagawan Vishnu’s names as ‘Om namo bhagawate Vasudevaya’ etc mantras are all Pouranic and not Vedic. In Vedas only Lord Rudra (Shiva) is the Bhagawan.
Not only this; in fact Rudram hymn has used the words “Bhagawate”, “Bhagavo” etc at many places addressing Rudra. Even Upanishads have greeted Rudra with this exhalted title.
“yo vai rudraH sa bhagavAnyachcha tejastasmai vai namonamaH |” (Atharvasiras Upanishad 2:19).
“He who is Rudra, he alone is Supreme god (Bhagawan). He is the Supreme Light and we salute him again and again”.
“tasyottarataH shiro dakShiNataH pAdau ya uttarataH sa o~NkAraH ya o~NkAraH sa praNavaH yaH | praNavaH sa sarvavyApI yaH sarvavyApI so.anantaH | yo.anantastattAra.n yattAra.n tatsUkShma.n tachChukla.n | yachChukla.n tadvaidyuta.n yadvaidyuta.n tatparaM brahma yatparaM | brahma sa ekaH ya ekaH sa rudraH ya rudraH yo rudraH sa IshAnaH ya | IshAnaH sa bhagavAn.h maheshvaraH |” (Atharvasiras Upanishad 3:6).
“The head of “the sound of Om” is on your left side. Its feet are on your right side. That “Sound of Om” is the Pranava (primeval sound). That Pranava is spread everywhere. That which is everywhere is the greatest. That which is limitless, shines like a white star. That which is also called Shuklam (seminal fluid- the basic unit of life) is very very minute. That which is minute is like a lightning power. That which is like lightning power is the ultimate Brahman (parabrahman). That Brahman is one and only one. That one and only one is Rudra, it is also called Eeshana, it is also the ultimate God (BHAGAWAN) and it is also the lord of all things”.
"Bhagawan" comes 35 times in Atharvashiras Upanishad, 2 times in Shvetashvatara Upanishad and 8 times in Sri Rudram hyms from Yajur Veda. So, in total 45 times in the Vedas and Vedantas (Upanishads) viz Shrutis, "Bhagawan" comes only for Bhagawan Rudra Shiva only and no one else. If anyone is counting Smritis as the 5th Veda then it's ok. It's common in there.
I hope this clarifies all your queries. Prd..