[kukkeliskuu]

I am just a student of these things myself so take everything I say with a grain of salt. But based on your question and my own experience, it seems that you are approaching religion in the same way I was doing -- intellectually.

That is natural, but the problem is that our intellect is quite limited. You would like to have a description of "the unifying deep truth". But even very simple experience, like how strawberry tastes like, cannot be transmitted by words and comprehended by the intellect. How could we transmit something vastly more complex even if we knew it -- and I am not claiming I do.

So I would say what you are missing is the direct experience of something higher. Seek and you will find.