Again. This presupposes that rich people, or rather people who can have "whatever they want", are predisposed to ennui at all. But there's just no evidence for this being the case. In fact, what studies exist suggest that greater wealth and fewer involuntary social obligations lead to greater happiness pretty much across the board.
Yes, rich people can get bored and unhappy. But using that as an argument to suggest that a society where everyone lived equivalently to the very rich would be an unhappier one is logically akin to arguing that society would be better off without flu vaccines because some people who are vaccinated still get the flu. It's using the exception, rather than the rule, to draw its conclusion.
I think a lot of people were moved by Endwalker - especially in the wake of, like you said, Covid and the slow death of the international order going on - because it ultimately preaches a comforting lie: That suffering is ultimately not only unavoidable, but good and necessary. Something that gives our lives substance and meaning.
But I just don't believe it. The truth is, suffering is only unavoidable. It has no positive side. If we'd been born into an advanced civilization 10,00 years in the future where unwilling strife ceased to exist, we would, by all psychological evidence, live richer and happier lives with no downside or loss of meaning whatsoever. That we were instead born in this moment in a time makes us victims of causality of a sort; we are trapped in suboptimal world for fundamental reason at all. Just like being born poor on a planet with people who can have their dreams granted with a snap of their fingers, it is unfair, cruel, and meaningless.
However, it doesn't bring me any comfort to indulge in fantasies that falsify the human condition, and pretend that a society filled with happy people would magically become miserable and lose their sense of meaning. Endwalker rings hollow for me for much the same reasons that I don't really get much out of Buddhism (well, at least Japanese Buddhism as it's usually echoed in media, since it's a very broad label). Rather than a philosophy of acceptance, of making peace with suffering and accepting it passively, I feel most emotionally honest and at peace with myself when it moves me to grief and indignation. I think it is beautiful to meet the injustice of the cosmos with kicking and screaming, and to never stop striving for the lives we deserve, even if they're unattainable. I could not disagree more with Yoshi-P's take on this topic.