I wouldn't have a problem with "mineru lied or was wrong" as the leading theory if there was anything in the game to support the idea that she could be lying
Which would again minimize the impact of Zeldas sacrifice so maybe I do have a problem with it actually
It's one thing to be like "I liked Zelda coming back at the end!" Vs "I didn't like Zelda coming back at the end!"
The fact is that the things you experience or feel CAN change based on new information. I enjoyed the plot twist of Zelda turning into a dragon forever. When it turned out that Oops, it's not actually forever, I no longer enjoyed the plot twist. This feels worse to me than it would have if it was just a crappy plot twist: imagine if all the foreshadowing just didn't exist and we had a cutscene of Sonia dying and zelda just eats the forbidden gummy and turns into a dragon. That's not as satisfying, even if you can then retroactively go "well see, eating the stone turns you into a dragon and that must be what happened to the other dragons, it was foreshadowed the whole time"
See what I mean?