Far too many people missed the narrative point of this scene, blinded by their dislike of a character.
You can dislike a character and still acknowledge their role and their importance in a narrative.
"Hear me then. Not as a hero but as simply...you"
"But there is more to you than than that. You know this to be true"
One of the only times in the game a character recognises us for US, not our accolades or achievements. The adventurer under the title.
"Acceptance at long last" is not Zenos saying we accept him.
It's not him saying we've finally accepted him or his proposed battle.
It's us - the player and the character - accepting our role, our position, beyond the Warrior of Light. That there is more to us than our title. Aside from our heroic endeavours, we do things just because we want to. Not for glory nor fame. But because we want to.
All the optional side quests, raids, trial series - such as The Warring Triad, The Four Lords, Ivalice and so many more. They have no over-arching impact on the main story. But we do them anyway. Because we want to.
We can choose to ignore them, choose to walk away. But we don't. We do it for us.
The narrative and thematic importance of Zenos is so obvious that it feels like being hit over the head with a brick, but people SOMEHOW manage to keep downplaying his importance to not only Endwalker, but FFXIVs entire overarching narrative.