
Probably because in Japanese culture it's generally seen as weird for women to express their sexuality strongly. Also, gay women seem to be generally more accepted than gay men in Japan, for whatever reason. I get the sense that being a gay man is seen as shameful, but being a gay woman is seen as hot. But that's from the male perspective only somehow? And it's the opposite from the female perspective? I could be wrong on that though since my perspective is probably skewed lol.
But basically, for the differences in the story telling, it boils down to what the author/editor thinks their general audience wants or would accept. That's true of most modern media at least.

That would be awesome, but I don't even hope for that much most of the time (there are a few Shoujo Ai Isekai that kinda do that, one of them got an anime adaptation but I can't remember the name). My problem is that Isekai MCs almost never have just friends. Sometimes I just want some wholesome friendship lol. I'm not opposed to a harem as long as the people in it act like actual people though.
When there are stories and it’s a man reincarnating into a girls body a lot of the times they get weirded out at the idea of them dating a man now. Especially if the man is reborn into a noble woman’s body it’s kind of expected of you to get married. In that same sense in the stories where a woman ends up inside a boys body they tend to allow themselves the freedom to fall in love. Are women just more open minded in that regard? I’m not necessarily talking about just this story honestly I feel like with his personality if the person just showed sincerity he may date them regardless of their gender. It was just a thought I had on the differences on how these stories are usually told.