Damn ur on fire. Giving off one good point after another. Based on what I datamined as well (I'm sorry I can't shut up about it), these endings are probably about the paths. These paths have almost little to do with Britt's gender (or who Britt is to them) and more about the captain's storylines (or who the Captain will be at the end of the story). This could basically just be 2 or 3 worth of lines and utmost 2 special CGIs after C9.from what was written in the patreon posts, each LI is going to have 3 possible endings- new world, old world and variant. each guy has a default ones if it is not changed in your gameplay. britt never saw himself as a girl in any of the chapters, so saying that he is going to end up as a woman in the relationship is harsh.
Maybe it has some impacts every now and then about the game (such as C4's Civil War or C5 Confidence Borge declining a runka), but the game is carefully structured not to make any changes that are too drastic to avoid bugs. Renpy is a pretty rudimentary engine after all.
The best example for this is actually Jostein. Bringing Filippa to Alfheimr on C5 barely has any effect on Jostein's storyline because one way or another, she's always gonna get sick in C6 ending. If she's in Himinbjorg, the cold is gonna get her. If she's in Alfheimr, it's the baby.
They did this because whether or not Filippa: (1) is well, (2) sick/miscarriage, or (3) dead, then the devs would be obligated to make at least 5 new Jostein events for each possibility moving forward from C7 to C9. That's 15 events per chapter, wherein players can only really view 5 per playthrough. But that's not what they did. Doing so would be too laborous for a pretty scarce payoff.
My point is, the devs making Britt trans for a few paths is highly unlikely cause they would basically have to double their amount of code. I guess they can make Britt trans in the main storyline (not just something that will be triggered because Jostein is too straight), but that would completely close off Kirk's and Ralf's romance paths + just mess up the narrative. Again, more problems.
I get that all these rising sentiments is really just a complex frustration that the game is not designed to be masc4masc. And on that point, I agree with poplo440's point that it doesn't suffice to label this as a "gay game". However, it is for a different reason. The worldbuilding and lore has evolved beyond making this a simple wank material. All these discourse on how femme Britt should be hardly matters to me in contrast to the plot.
Lastly, the itch description does explicitly say "for LGBT adults" and "If you are looking for porn, you may not like this game". It does say "Boys' Love" and "Gay" in the tags but I reckon it's for SEO purposes. This game is still pretty gay after all – just a really complex metamodern type of gay.