I think Julian Baggini is spot on here. Too often the project of combining aspects of religions, philosophies and mystical traditions from all cultures devolves into logical incoherence. To the extent that there are extremely broad commonalities, it’s because these traditions satisfy common human needs. That is the “deeper truth” we can find from comparing how they overlap.
That’s why I find phenomenology a much more compelling way to look at how they overlap. Why are we so hungry for philosophies of transcendence? What hole does that plug?