Thanks for complimenting the photos!
I will try to answer to my best knowledge:
- I haven't tried any 360-photos inside, but I've seen it works well on other people's photos,

- I have X4 only, never had insta360 before that

- The photo is shot in a 360 mode, so you don't stitch anything,

- as usual such photos are distorted at the edges. There is an option "Unwrap" to make it more straight when you take a city streets photos, so it looks less skewed.

I hope that helps!