It depends on how you define "polytheism". As Swami Vishwananda explains, the nature of "divinity" in Abrahamic religions is very different from the nature of divinity in most other religions.
The Atman and Brahman are concepts from the Vedanta branch of Hinduism that represent respectively your individual consciousness and universal consciousness. These are fundamentally pantheistic perspectives.
And while controversial for sure, the notion of universal consciousness is not alien to modern science and can in fact be fit perfectly into a modern materialistic scientific worldview! Notions of the universe as a giant hologram or a giant quantum computer are different more at the semantic level than in their essence, really. How distinct from each other they really are pretty much depends on how you define "consciousness".
The Trimurti - the Hindu trinity - can easily be understood as mere anthropomorphic references to the three primary forces in nature that hold the universe together :
- Brahma (order), the source of creation, can be understood as an anthropomorphic representation of emergence
- Shiva (chaos), the source of destruction, can be understood as an anthropomorphic representation of entropy
- Vishnu (balance), the source of balance, can be understood as an anthropomorphic representation of the laws of thermodynamics
So, once we reduce these principles to their very essence, we're left with concepts that are totally scientific.
Much the same way, Shinto's Kami, Hinduism's Devas and Ásatrú's Götter are all just anthropomorphic Animistic representations of lesser natural phenomena. These, also, are totally distinct from the "God" concept that we find in Abrahamic religon. And here, as well, we can often just reduce these concepts to their essence to be left with either scientific concepts or concepts wholly compatible with modern science!
So, unlike for adherents to an Abrahamic religion, it's actually pretty easy for adherents to so-called "polytheistic" religions to find support for their perspective in light of modern science. All it takes, really, to make sense of their religion is to look beyond folkloristic myths (often created with the explicit purpose of teaching complex ideas to simply folks) and silly superstitions (which are often later additions) and reduce the core religious concepts to their very essence.
What's left, are wholly rationalistic philosophies that can easily be mapped to concepts from or compatible with modern science. Knowing this, it's easy to completely discard Abrahamic religion in favor of any flavor of "polytheism".
See also my article The Atheistic approach to God… or how to bridge the gap between Atheists and Theists where I explain how Atheism, Pantheism, Hinduism, Animism and Shamanism are really just different perspectives on the same core concepts.