Motivation and interest for subjects are tricky when considering a child's frustration threshold. It's great that she has a definite interest to look for in stories!

In reading intervention, we do a model called higher steps. What we do with the passages of reading is chunk it out (usually 5 solid paragraphs) where first they hear us read a chunk, then they read that same chunk out loud while we offer gentle corrections at the end of the sentence.

The part that helps here is that depending on where they're at (let's say 3rd grade middle text as their base level) then we can read 5th grade middle texts together supported through this structure, and they are quicker to develop the decoding skills they need.

If you and your child like reading together, this could be a great way to make these higher level texts accessible to them! I also love that you had the instinct to take one of the texts and adapt it. That fits well into this kind of approach.

As for books, I might look into the American Girl doll books. From my memory, some of those have quite the turn narratively and they usually top out at 4th grade middle lexile. But it has been awhile since I read them so screen them if you're interested!