Wow! No one can accuse you of not thinking enough, and you outlined a laudable mission, but while I was reading your post, I was thinking, "Hey, WhatsDone, slow down and just take on a few things at a time. Maybe only one thing at a time. Keep in mind that not all the questions you ask may have answers, and you have to live with that much of the time.
We all have ego issues. The nature of sentient life is that everything we perceive and react to goes through our brains, not some collective consciousness. We are literally at the center of everything around us so yes, we are egocentric by evolution or design. It's probably not the ideal, and it certainly causes us grief, but it's who we are. We try and temper it as best we can, but none of us will ever be perfect.
As for ultimate truths, the finest philosophical minds haven't figured that out, and they've been working on it since Plato, so don't expect to figure it all out overnight.
As AAPJ said: "An ultimate truth? I don't see it. At least not for me. For me the goal is to move in a positive direction. Progress not perfection. " And you've got your whole life to work on it, and you're not going to complete it, even if you live hundreds of years, so slow down and enjoy the journey.
It's good to have you here.