In your opinion, which moment sticks out as the absolute lowest point of the series? The absolute nadir of quality? Be as specific as you like - can be a moment from a game, or a whole game in its entirety if you can't pick.
Also, what about the opposite - the highest point? A moment so good that you felt FE had reached a new peak of excellence?
For me, the lowest point has to be the dynamic between the Nohrian family in Conquest. The moment-to-moment writing is atrocious, but I doubt even John Updike could have saved the overall arc of the story itself, regardless of the specific lines of dialogue.
Another contender is the entirety of Fire Emblem Heroes. I can't even begin to describe how much that gacha dogshit bothers me, and the influence it has had on the direction of the series as a whole is extremely depressing.
The highest point for me (so far) is when Alm and Celica's routes merge in Valentia. I don't know what it is about that game, but it's far and away my favorite so far.