I like Endwalker story, and I was enjoying the plot. My personal criticism is only at these points:
1) Structure of plot is very similiar to Shadowbringers. Dungeons and trials are at similiar points, and Dead ends with expansion villian narrator was just the same idea like in Amaurot. If something is so much similiar, it becomes predictable. And this is something what as storyteller you want to avoid.
2) I was dissapointed with idea of Meteion as last boss. When we defeat Zodiark and it turned out that because of vanishing ambient eather world was in fire, to me it was so much better concept to stand against inevitable, nature caused, world ending catastrophe without specific solution. When it came down to killing one girl, for me it was just like "monster of the week" episode.
3) Second thing that I do not like in Meteion and what I do not like in dynamis that there wasn't nothing foreshadowing them in lore. One of many reasons why people dislike Jailer from WoW is that he was introduced at last moment of story that was talled since Warcraft 3, and he is responsible for everything what happened in game since that time. Much the same you can tell about dynamis and Meteion. of course she is much better wrote than Jailer, but for ending of 10 years ark, I would much more appreciate ending that would use plot points from everything what happened since ARR and use them in finale as checkhov's megaflare gun, than some emo girl and new nature force added to game at last moment as one of most important plot point.
If i'm wrong about this point and dynamis and Meteion were presented sometimes between ARR - SHB expansion or at some page of Encyclopedia Eorzea, I will appreciate if someone show it to me.
4) That is more of my wish than a true criticism: I hope that FF XIV will at some point break world record for the longest cutscene (currently hold by MGS4). Ending was good opportunity for that. But I know that many players don't want long cutscenes, so - as I say - it's only my, personal wish.