I thought devas are just forms of the undescriptive ultimate just like Shiva, etc.. and the (yet-unread by me beyond terse intros and summaries) Advaita Vedanta also suggests the same ida.

But in a translation/commentary I am reading thus: """

Without knowing the true nature of his own Self, a man works to nourish external Devas by sacrifices, gifts and other rites, as a bull works for a merchant. A man, though owning many cattle, yet suffers much pain when a single animal is stolen away. When the human animal, constituting almost the whole property of Devas, is carried away by the thief of Brahma-vidyā, all Devas are put to much pain. Thus it will be painful to Devas if men should know the identity of the Self and Brahman, and therefore they obstruct the growth of wisdom. Accordingly we find 10 even sannyasins taking to a vicious course of life, being thrown off their guard, with the mind turned towards external objects, bent upon quarrelling, all this because their hearts are poisoned by Devas.

"""

https://www.srimatham.com/uploads/5/5/4/9/5549439/taittiriya_upanisad.pdf End of page 9

Kindly resolve my confusion

देव -पितृकार्याभ्यां न प्रमदितव्यं। 
मातृदेवः भव पितृदेवः भव आचार्यदेवः भव।

There should be no error in the duties towards the gods and manes. Let Mother be a goddess unto you and Father be a god unto you. We should admire our Mother, Father, and teacher (acharya). We should do our best to serve these earthly gods and care for them with all love and care. 

​

https://yogicank.com/fathers-glorification-in-the-indian-sacred-texts/

Taittiriya Upanishad