Recommend short books for a friend getting into reading again?

I have a good friend who has a couple preferences like

1. no autobiography’s
2. educational books about nature and the natural world are fun
3. Enjoys fantasy and short story collections
4. mixed about romance

By short they mean a read in five hours or less.

They enjoyed Harry Potter although as far as I know had mostly focused on the movies as the books were too long. They were a big fan of all tomorrows though they stuck to the audiobook. If you could include spoiler free small summaries or what got you into the book as well, that would be nice, but optional. Trigger warnings if possible would be appreciated if it touches on sensitive topics.

if you have something outside of the genres listed, feel free to add if you believe it is still short and captivating but mention it isn’t as listed so I know to mention that to them.