According to PC Gamer, Igor Sarzyński had this to say:
"The endings are written as we wanted them—leaving players with an uneasy feeling, forcing them to think, not providing straight answers... They stick with you. No need to water them down. Sometimes less is more."
Which, I dunno if that was successful? I really don't know. If your writers have basically committed to the above principle, or "rule", then the risk is that you make your endings conform more to the rule than to the story. If both things line up, then it's fine - but if they don't gel with each other then it's harder to stick the landing possibly?
E.g. I think it works with the Devil ending, because it's meant to feel "uneasy", and that's congruent with the choices V made to get there and the theme they chose to resonate. The Devil theme is very Icarus, very cautionary tale, so it just... works. Plus if you choose Mikoshi it becomes extremely logical why you wouldn't conclude the main conflict of the story. But even if you choose Earth, it stills fits with the theme anyway.
But with the Star ending, it's trying to feel hopeful. The theme there is freedom and hope through family or whatever. Which doesn't really gel well with the fact that V's priority still seems to be "I need to find a cure" - well you're not free then and the main conflict is ongoing. So, to me, that's an example of making your ending serve this arbitrary idea you have that "it needs to feel uneasy and vague!" rather than serving the story.
And actually, the new Phantom Liberty ending is an even more obvious example of this problem, where the nomads inexplicably shun V - it just felt forced and done for the sake of the "rule" again, rather than what would realistically happen.
That being said, I do think Phantom Liberty has added so much more context now that actually the Star ending actually does earn the hopefullness it implies. Same with the Sun ending.
So perhaps there's a happy accident or a stroke of genius in the writing in that regard?
We now know there's no such thing as "can't be done" regarding curing V. You just need to find the right experts, and you now have plenty more time to do that. We also know we're on Mr Blue Eyes' radar (and if you saved Songbird, you probably have her allyship as well). We also have reason to hope that there are benevolent forces watching over us, such as the Zen Master and whatever it is that's showing us the tarot cards (which would suggest that Star and Sun are the right choices).