How to write a book: Inspiration

Sometimes it's hard to get an idea for a story. I've heard a good place to start is putting your spin on fairytales retellings. Maybe a modern day Snow White told from someone else's POV, etc. My inspiration came from Hawks in My Hero Academia. Yes, you read that right. His character is fascinating, but I didn't want to copy Hawks. I thought about what if scenarios that evolved over time to explain the existence of such a person.

For example: if I told a story about a winged character why would they have wings? Did anyone else? How would people react if they didn't?

I suppose I could've created an angel story. Instead, I decided to lean on the wings being animal traits. After A LOT of back and forth I decided against making the entire world have these wings and tails, it just didn't work. I looked into folklore, reading up on what could fit my idea. Mixing the concept with my own worldbuilding helped create an entire world.

Do you know what the funniest part about all this is? The winged character I planned isn't in my book. If they ever appear they likely won't be starring in a book. Why? The story changed to the point it's completely different from where it started.