Didn't really answer the question why she wanted to reboot civilization all the time... initially i thought it was due to balance of planetary resources to avoid depletion through industrialization. But the ending suggests otherwise and resources were not the choke point in why she kept resetting civilization. So what WAS it all for?
Having just read the whole story in one sitting, I think that basically, society imploded due to technological advancements causing a lot of damage to the earth and ultimately leading to wide-spread wars. First chapter gave the impression that Earth was in really bad shape overall, and I got the impression from the flashbacks that Earth and humanity had already been in their twilight years at that point. A bunch of scientists got together to try to save the world, but Eve decided the best option was to just do a hard reset. Basically the "nuclear war can't happen if they never reach the point they start developing nuclear weapons" mindset, with a touch of eccentricity added in.
That said, while the manga ended in a pretty nice way and didn't feel rushed, I
do think the author could tell the numbers weren't strong enough to guarantee continued serialization so they changed gears to end it on their own terms. I feel like there were some plot threads that were meant to lead somewhere, like how the demon lord at the facility with the kids apparently disappeared. And in that same arc, Noah used a disguise and said that's what he originally looked like, and we also saw a silhouette of him with long hair when he transferred bodies which didn't really match up with his flashbacks.
Also worth noting that the robot AI and ship, "Ark", was... well, called Ark. And it was a spaceship carrying a person named "Noah", and then her own name was Eve... I'm guessing the
original plan of all the scientists was to make an actual ark for humanity. But Eve was eccentric so she decided "screw that plan" and went for a hard reboot for a world without technology to try to prevent it from ever occurring again.
But since the author saw the writing on the wall, they altered the story to remove that backstory so they'd be able to give it a well-paced and proper ending. Makes me a bit sad the author didn't have a chance to feature everything they wanted.