Split View not available with some combination of apps.

Hello, hope you are well.

I have a problem with Notion and the split views. With some apps it works, but when I try to have a Split View with a book and Notion, it says it's not available. I've tried opening the book with different apps, such as preview and Books, but it doesn't work. Is there a way to solve this? It would help me greatly, since I usually need to read the book while making my notes with Notions.

I have a MacBook Air M3 btw. Thanks for your time!