The full passage of the Upanishad relevant here is:
य एषोऽन्तरादित्ये हिरण्मयः पुरुषो दृश्यते हिरण्यश्मश्रुर्हिरण्यकेश आप्रणखात्सर्व एव सुवर्णः ॥ ६ ॥
[Now that golden Personality who is seen within the Sun, with golden beard and golden hair, and golden all through to the very nail-tips.-[His name is Ut-next text.]-(6)]
And the next mantra 1.6.7 which means: His eyes are of the color of a lotus....
तस्य यथा कप्यासं पुण्डरीकमेवमक्षिणी तस्योदिति नाम स एष सर्वेभ्यः पाप्मभ्य उदित उदेति ह वै सर्वेभ्यः पाप्मभ्यो य एवं वेद ॥ ७
Shankara says in the BSB 1.2.14 that even though Brahman is nirguna, yet in order to help upāsana the Upanishads permit saguna attributes such as name and form to it in the form of 'this is its name' (Chandogya 1.6.7), (it has) golden beard, moustache, etc (Chandogya 1.6.6). saying this is saguna brahma upasana:
In the Bhagavatam we have an application of a few of the epithets stated in the Chandogya Upanishad:
ज्ञानविज्ञानयोगेन कर्मणां उद्धरन्जटाः ।
हिरण्यकेशः पद्माक्षः पद्ममुद्रापदाम्बुजः ॥ १७ ॥
[Then He spoke to Devahuti:]
“O princess! The very Lord Śrī Hari — who, in the form of an infant with golden hair, lotus-like large eyes, and feet marked with the lotus, slew the demon Kaitabha — has now entered your womb.
In the Shiva Puranam we see those very epithets applied to Shiva:
शिवपुराणम्/संहिता ७ (वायवीयसंहिता)/उत्तर भागः/अध्यायः ०६ https://sa.wikisource.org/s/hze
हिरण्यकेशः पद्माक्षो ह्यरुणस्ताम्र एव च ॥ ७.२,६.१४
यो ऽवसर्पत्य सौ देवो नीलग्रीवो हिरण्मयः ॥ ७.२,६.१५
He is Hiraṇyakeśa — the One with golden hair,
Padmākṣa — the lotus-eyed;
He is also Aruṇa — reddish, and Tāmra — copper-hued. (7.2.6.14)
That divine Being who descends (or manifests) is Nīlagrīva — blue-throated, and Hiraṇmaya — golden in form. (7.2.6.15)
Here we have three epithets from the Chandogya Saguna brahman marks.
Thus, Veda Vyasa applies the Upanishadic SB epithets to Hari and Hara alike. In other words Veda Vyasa agrees that both Hari and Hara can be contemplated upon as the Saguna Brahman of the Upanishads. This premise is admissible only in Advaita.
warm regards
subbu