Repetitive storytelling is kind of par for the course in an MMO plot. There's always going to be yet more dark gods to slay. More evil overlords to depose. More oppressed people to save. Complaining about monarchies specifically is a hill I have no interest in dying on, and since half of your arguments amount to "I just don't like it", agreement was never really feasible. Understanding, at best.
Doesn't change the fact that they're monarchies.
He's a satrap, which is a monarchal position. Before him, a family of monarchs ruled as the puppet government. The fact that he doesn't age changes nothing about that, since he could always be killed or step down and personally name or father a successor.
So we've moved from "the game is against monarchies" to "none of the ones that exist do it for me anymore".
Ala Mhigo doesn't want another dictator since the last one was literally called the Mad King. They literally held a conference to decide.
Eulmore is basically just "I don't like it".
No comment on Ishgard. It's not that different from what we have, except Aymeric just isn't wearing a crown. No comment on Bozja, either. That wasn't even written by the same writers as the rest of the game, and he had to rush the ending...so meh.
Garlemald? ...Yeah, I'll get to Queen Waifu in a second.
That seems like it misses the point and/or goes against the entire characterization of said monarchs.
Thordan's goal was to become Emperor Palpatine and live forever as a god-king with no need for an heir.
Ala Mhigo's entire royal family died decades ago.
Eulmore was run by a manchild whose entire philosophy was that the future didn't matter, so party it up now.
Bozja did have an heir, and she turned out to be insane.
Most Garleans literally scoff at the idea of women rulers, and have no interest in anyone ruling who isn't a generalissimo. The idea of some Disney Princess showing up and melting the hearts of the Garleans sounds like an even more boring and unlikely outcome than any of the others.
So in other words, you want the Scions to rule? That's what it sounds like you're saying. Because in each of the games you mentioned, the endgame is a player power fantasy that ends with various members of their party either as ruler or consort to a ruler. All hail Archbishop Thancred, Queen Lyse, Mayor Alphinaud, and Emperor G'raha!
Besides that, all of these "solutions" really say to me is that the problem isn't repetition. It's "do the repetition that I like". By your own admission here, you had no problem with the same conclusion in three different FF games (and twice in one of them).
This part I don't agree with. If I could go back in time and stop the genocide of the Indigenous Americans, the Crusades, the Transatlantic Slave Trade, the Holocaust, and many others, I'd do it even if I ceased to exist.
Most of these things are the reason the current world is so effed up.