Why not that the hunt for "essences" is a dead-end? Yet again, you beg the question.
That depends on how we define essence. But it surely will always be a generalization. No doubt about that. But such is the nature of social phenomenas. You can never fully comprehend them, so you generalize to get at least as close as possible.
As said, in this context I understand essence as what defines a specific social institution. And by defines I mean what is its fundamental difference to other social institutions.
In case of religion, it is that its foundation is of a metaphysical nature by definition. You can't have religion without that. Then it is an ideology or whatever.
And then one may ask what does this metaphysical nature offer others can't - so again what defines it? I would say that there are no direct constraints by the observable world to its message.
And to what purpose is that used? Naturally, to serve the emotional needs of people. But again we may ask, in what way can those metaphysics serve emotional needs other things can not? I would answer that with an absolute and universal source of meaning (and hence in a certain way security, orientation), not constrained by the limitations of the observable world.
And that's where I arrive at the conclusion:
The essence of religion is the emotional need of people for an absolute sense of meaning.
I personally don't care how that is achieved. But it is my impression that every religion does that. Of course, I can be wrong and would be very interested if you knew a religion which doesn't.
However, how such an essence actually determines religion is another question and leaves much to be argued, I can agree on that.