What confuses me a bit is that I've seen some takes about genderfluid Ralsei or galsei where they're like "Ralsei's title doesn't have to dictate gender, Ralsei can still stay a prince if they're trans" and like yeah, but... that kinda misses the point?
We still have 2 scenes that are about Ralsei being explicitly a Princess in the game (quick intermission in case of genderfluid Ralsei, I don't think Princess would be an outlier from "title doesn't have to dictate gender" in general) and if you're just trying to find a way to make Ralsei still fit into the Prince title then what was the point of those scenes being there, firstly,
and secondly, the cool thing about trans Ralsei was also that Ralsei gets to realize that the prophecy can be wrong about things, or that it might actually be changeable, and thus giving them hope that maybe all they need lies in themselves to subvert the ending. That doesn't work if Ralsei is still stuck in the Prince mold.
The fandom in general has a lot of problems with still wanting everything to fit the prophecy with "Ralsei is the girl, and Lancer can be the prince" or "Asriel is the prince and Ralsei isn't actually in the prophecy".
Free yourself my siblings in fandom, the prophecy is a cringe-ass loser fraud, we don't want to appease it!