We already have high level answers to all of those except Orion's nature though, and the details don't feel all that impactful. It's like the difference between knowing about Zion in The Matrix, and seeing Zion. Did seeing Zion really feel expansive?
Eternum is just there, the way our universe is. What is the purpose of our universe? What is the purpose of our solar systems? The Founder is just some dude with really high compatibility who saw a way to profit. We already know Thanatos is one of many who have been transplanted permanently into Eternum, and he has Hyas. Idriel is a slave of the Founder, and the Immortals are oppressors.
Nothing you've said is close to an answer to anything. Those aren't even high level answers. It would be difficult to be more vague.
Why not give the same type of answer for Orion's nature? He's that way because he is.
It's good that scientists didn't take the same approach to our universe and solar system as you do to Eternum. We'd still be living in a world where everyone believes gods make thunder. "Purpose" is a loaded word. Can be used to ask "why does the universe exist?" (probably unanswerable) or "why does the universe behave in a particular way?" (sometimes answerable).
We don't know the details of the answers, so you can't argue whether they will be impactful.
This is one little unfortunate thing about all of Caribdis' works in principle. It's ALWAYS been there. I love his central messages of "Don't be a scumbag" and "Don't be a pussy".
However...
There's just a wee bit too much emphasis in his games of "or else other men are gonna fuck your girl" that none of the other top visual novels have (BAD, Ripples). He's definitely more focused on the competition between men for women
I don't see you how you can say there is an emphasis on "or else other men are gonna fuck your girl" because that doesn't happen and isn't implied. You can reject or fuck up with every one of them and it does not happen. You have zero competition. Who do you think is competition? Chang? He would never (and he has Micaela). Jerry? Not a chance. Axel? ha!. The other male side characters are either uninterested, inconsequential, or scumbags whom the girls would not consider in a million years.
There was one scene in OIAL where it could happen to a single character and you had to actively decide to do it (and I think it led to a bad ending).
I don't even think the suggested vibes in the office sequence are much of anything. I know they're talking about the TV section, but this is a dream sequence designed to mess with Orion's head, and nothing happens.