Gutencraft divides text into copy-pastable pages to fit into Minecraft books.

Use the webpage: https://nightlynexus.github.io/Gutencraft/

See the demo: https://youtu.be/yOT-ZSNCexg

Jars of the Java app are also available at
https://github.com/NightlyNexus/Gutencraft/releases
but the webpage is faster.