I think there's something about aggro and aggressive vs passive enemies that affects targeting priority and that might have had something to do with it
I've tried tab targeting with like 5+ enemies aggroed on me and the game is like, "oh do you want to target the passive unaggroed enemy 20y away and not one of the five guys currently punching your face?"
and yes it is extremely narratively appropriate that you don't bother to learn Grynewaht's name, despite all of his namedays coming at once, all the time
I think he only refers to you by your name like once. The rest of the time he just calls you "Eorzean," like, not even Warrior of Light. Just "Eorzean." Even your other enemies call you Warrior of Light.
I'm not sure how it is on controller but on kb/m the weirdness from tab targetting comes from being based on distance from the centrepoint, which literally no other game does