It's kind of interesting that Ancients other than Hermes didn't really seem to care about space and the wider universe at all. Of course I understand that their entire philosophy is that the star and betterment of it comes first and foremost, but the idea that everything beyond Etheirys would be so neglected to the point where an energy source that compromises most of the universe is some kind of fringe topic of study is strange. I don't know if I can attribute it to a writing quirk or if there is a sensible reason for a scholarly society like the Ancients to know about it, yet willingly choose to not research it further, when it doubtlessly could have had use in understanding the nature of their world, and thus, have a better idea of how to nurture the star even more. The fact that all of what transpired in Endwalker occurred due to the acts of a single Ancient leads me to wonder what they could have accomplished if they had a group dedicated to similar pursuits.