Would the mixing of different types of the same animal be counted as the same thing or a hybrid

Sorry if this is a dumb question, but I’m currently writing a fanfic using the world building of beastars, and one of the characters is a siamese cat and maine coon mix. Since it’s the same animal, just different breeds, I’d figured it would be okay. She isn’t supposed to be a hybrid, and this is the closest thing I could think of that wouldn’t be just the same exact breed. I know it wouldn’t really matter since I’m making up some world building for it, but I want to follow canon as much as possible.

So sorry if this is a dumb question, but would mixing two different breeds count as a hybrid, or just the same animal.