I think people are forgetting that bi, pan, and demisexual people exist. The original novel isn't stated to have said that Edwin is strictly mlm, same with Michael. The only thing we got from the novel is that Edwin's obsession towards Michael was due to Michael helping him out. Now that Alice (Elizabeth) took on that role, it's not surprising that Edwin ended up falling for her? I agree with your last comment, I don't know how they're going to turn Edwin's obsessiveness into a healthier kind of love.
I'm bisexual myself but I don't turn 'straight' or 'gay' because I'm in relationship with either I'm still bi. Honestly it's also a problem with a lot of BL and GL novels bi erasure but I still don't like this novel because it gives me conversion therapy vibes like it doesn't feel like he's bi but that he just became straight.
I hope I was able articulate my thoughts well.
I think people were misinterpreting the OG story... It was a BL because Edwin was obsessed with Michael ... Obsessed coz Michael shows a bit of kindness and lift up Edwin's cursed... It is not real love coz it doesn't have to be Michael... If anyone else did it, then Edwin's obsession will direct to that person which is the current plot... Now it will be a challenge to the author to make Edwin grow out of his obsession and actually truly fall in love ┑(￣Д ￣)┍