contemporary polythiestic devotion

Seems like a problem of metaphysics. You need a metaphysical framework that addresses the contemporary situation.
And it can be found within polytheism. Some things that the pre-christian faiths of Europe identified are vital, still live within the landscape, and the supplanting religions have failed to address them (and may be unable to address them due to the metaphysical foundations of these new religions).
Central to polytheism is that the gods exist.
Understanding how to approach them as a contemporary devotee can't be dealt with through treating the gods, or an amalgam of deities like the 'higher truth' in a 12 step program, some benign and characterless force that's there to be an object of strength for you you, or by the bland reconstruction of some arbitrary point in the history of whatever pagan tradition you are following, which is then the -one true way-. It requires an understanding of the gods, and how people understood them throughout history, from prehistory, the classical era, late antiquity, the renaissance, enlightenment, modernity, and now*.
The other part of the equation is the human. The nature of man hasn't changed, and millennium of attempting to impose upon him what is alien to him falls away so, so easily. Which is why we return to the gods. That said, our understanding what man -is- has changed, vastly. Things which the odd philosopher 2500 years ago only guessed at, that man came from animals, are now known to be true. Add dozens of other revelations about how man thinks, how our society is organised effects us, and all kinds of other stuff, and it calls for a certain iconoclasm against things like myths of origin that became cemented with the event of writing, for example.
But with all this said, there are metaphysical questions, which fall into the realm of religious mysteries, that exert a heavy influence on how a religion exists in the world. And since they are mysteries they are unanswerable by reason. So there will always be an array of answers presented. Things like the origins of the soul, and what happens after death, that can only be -finally- resolved by magical proofs. In practice they will be (most productively) shaped by the goals of the religion, or (less productively) stumbled into, and will be arrived at either personally, or by taking the word of some leader.
*yes, eras of various traditions vary, the order in the example applies specifically to the classical religions, i.e. Greek and Roman.