Oh 😂 😂 gotcha
Do you remember which hatchery she came from? That's one place to start. There's also test you can get done but honestly, it's not worth the money to me.
Just let her live? Knowing or not knowing her breed usually isn't any issues for backyard chicken keepers. I have a few mutts that I don't know what they are. They're nice girls and good layers so they have a home here until they pass.
She kind of looks like a molted Ancona to me but her leg color is definitely wrong. Honestly, I'm not sure what she is. She doesn't have the body shape for an australorp either.