Since the illusion of choice was so shattered by that ending, the obvious thing would have been to just focus on writing a good general story wrap-up with things built up to regardless of player agency. See: Whatever JRPGs that don't go for some "subversive" or "mindscrew" plot ending. Actually, maybe a subversive one could have worked; After all, the illusion of choice was already destroyed, so you may as well roll with it and explicitly un-do choices the player made to rub it in, at least then the player might think there's some kind of narrative purpose in subverting their options. But yeah, I was thinking more along the lines of a typical "trilogy" ending would be serviceable. You could even reduce the budget required for this since you technically wouldn't be writing "3" very similar endings.
Heck, let's make an exercise out of this; Imagine the ending is mostly the same but the game makes it a point to discuss your lack of options, rather than put up a mask with fake options. I bet a simple detail such as that would improve the ending.
