Hello, the feminine and masculine part is almost inexistent in English (comparing it to other languages) especially when the game directly talk to the main character (with the use of “You”). And the fps view can often let you imagine your character. An good example could be “Legend of Grimrock” for the large part given to your imagination with no 3D models for your characters and it works it’s more immersive(you can even choose you own portraits for your characters).

Hello! I'm sorry but I'm having a bit of trouble understanding what you're asking and need a little clarification. Are you asking if it's okay to write or make a game that's in a first person point of view, without a visual for the person you're playing as? Because it is, absolutely! So long as there is a main prominent character that is clearly nonbinary in your game, then its fine! :D