Indeed, there is only one truth, one reality. As for your question, it's not that complex once you know that truth. And it's not hard to know it either. As you say, one must let go of all preconceptions.

https://senderspike.medium.com/christ-buddha-and-the-new-reformation-92583edd35aa

Just as a side note, and a small exercise: God, Tao, Brahman, simply the Absolute, is in all traditions described by the same adjectives -- omnipresent, omniscient, omnipotent, omnibenevolent, but also unchanging, etc. Now, the most straightforward way to "reunite with God" is to answer the question who or what is everywhere at all times while it is always the same. Obviously, that which merely permeates or stands next to, no matter how close, does not fit the bill. Neither can the changing forms satisfy the condition. And so on and so forth. Anyway, once you "crack" the problem of omnipresence, the rest will simply follow.