It's a huge conversation, I've had pieces of it several times. It boils down to one frustrating stopping point tho. We simply don't know because we have only our own planet to study and all life here is related.

That makes almost everything we csn talk about here speculation built atop a house of cards if assumptions. The only reasonable things we can assume hinge on the life having followed a very similar path to our own, and the odds of that may or may not be likely to have happened twice in the same meaningful span of distance.

Worst case scenario, the odds of intelligent, technological civilizations being within 20 billion light years of each other is low. But it could be even worse. It could be an average of a trillion light years and we might be alone in the entire observable universe.

If we could figure out how life formed and master recreating it in a lab, we'd be able to speculate a lot better about the odds of it happening. But until then we're really grasping at straws when we say anything about life outside earth.