I agree. Self-insert is indeed tricky to pull off, but the devs have already accomplished this well. At the end of the day, this is currently a self-insert VN. Not every detail that's incorrect breaks immersion, but big story moments like these do.
Certain aspects of position roles can indeed be toxic, for example, such as having Asterion be a bottom simply because of his trauma, submissiveness, and need for guidance. It's ok to have different story scenes based on the user's decision-making throughout the game; it's already been done for other scenes. Best part, it wouldnt change Asterion's dialogue at all.
People have preferences. It's not inappropriate to suggest more inclusivity for a visual novel still in development, based on the user's experience of it. Frankly, the dev team has full control over the way this story is told and eventually released. Whether they consider what their players ask for or not is completely up to them, and the direction they have planned for this VN. Even if they don't add things like player positions, personally, I will still play the VN, as its foundation is strong. The development team shows care & love for this project, and it truly shows.