I’ve definitely thought about introducing romance routes. Ideally, I’d love to include multiple options toward the end of the game, like individual romance routes and even a harem route. As you mentioned, some characters lean more toward romance than casual relationships, so it feels natural to incorporate that. That said, it's a lot of work, so it might take some time before it’s fully implemented! You're right about the MC being bisexual and attracted to both genders, regardless of the chosen route. I understand that may not appeal to everyone, so the best way to handle that would be to offer separate routes, one strictly straight, one gay, and one bi, so players can choose what suits them without feeling uncomfortable with certain content. However, the MC is still canonically bisexual.
All of that sounds great actually, and don't worry ab how long it takes. It's game development, narrative crafting, and worldbuilding all rolled into one, don't worry ab the fact that you need time to do those things. I'm looking forward to seeing how everything progresses. I wasn't expecting to actually be enthralled by the story, but there I am (oh and I have to add that so far, I absolutely adore all of the characters and the art style is so cute)