Well, it's typically referred to as having a fictional crush. It means you're deeply attracted to a made-up character and might daydream about them. It can be a fun escape but also a bit strange to some people.
It's called fictional infatuation. It's when you have strong romantic feelings for a character that doesn't exist in real life.
This is often called fictional love or a fantasy romance. It happens when a fictional character captures your heart and you build an emotional connection with them in your imagination. It's not uncommon among fans of various forms of fiction.