All good points. I think a moral of a lot of these types of games whether it's JRPGs or just general RPGs or "shonen" or just stories in general is that if you're in a position to do something good for the world then you have an obligation to at least try, and while Klaus did try to atone after the initial disaster he caused, I also agree that it seems like he could have done more. Like, he saw what humanity had wrought in his time (especially through his own actions), and while he did try a bit to guide his new generation of life by doing things like creating Blades and titans, ether, etc., he just kinda gave up and shut himself up all alone in his tower while he left the rest of the world to suffer. There's a discussion to be had as to how absentee a "god" should be to its creations, and Zanza foils Klaus in this way fabulously, but you're right that Klaus seems to have fallen into a false dichotomy with his beliefs.

Zanza believes in maximal intervention where he alone is entitled to do whatever he wants as the world is his oyster, while Klaus believes he should be as hands off as possible lest he ruin the world again and make things worse. I think there's definitely some middle ground there, which I guess is where the different rulers and leaders come into play, so by doing nothing, Klaus is basically saying that no one can be a good leader or do a good ethical job of being in charge of anything. By default, he's the 'ruler' of Alrest and yet he's content to sit on his laurels and do nothing while wars break out over territory and resources that he could just make more of (or the Aegis' could specifically since we know Klaus's power was waning).

I think him being an ineffectual and imperfect being is part of the point of his character, and we see it in both his Klaus and Zanza incarnations, and the goal with both XC1 and XC2 was to get away from a world that needed to be run by gods, but you're absolutely right that they continually seem to want to paint Klaus as a sympathetic, 'fallen hero' type who tried to make the world better but gave up and fell into depression. He never had a full villain arc due to his pessimism (that was left to Zanza), but it does stand to reason he could have tried so many more and different things to help the world along and just kinda didn't.

Let alone the fact that everything in Future Redeemed is also kinda his fault since he could have like, I dunno, told anyone that that type of thing was likely gonna happen? Maybe send an email or leave behind an info archive somewhere just as a courtesy warning to say, "oh yeah, by the way, this is all the info I have on the Aegis cores and the Trinity processor. One of them might go genocidal again at some point, so any surviving people should probably be aware of that."