I feel like the message got clouded in hearing too many antagonists give their own bleak philosophy at length, without giving enough voice to a more hopeful counter-view.

I think I need to play the game through again from start to finish (I have an alt nearly through 5.X so will replay soon) and see if I still feel that way the second time around. But at least as an initial reaction, I preferred Shadowbringers.

I also found it too cartoonishly improbable that every society the Meteia discovered had already crumbled in some bleak way. Perhaps it might make more sense if she had found young civilisations in their prime contrasted with old ones in decay and concluded that all were doomed to fail in time?