Hello! Mod is awesome, but!
I was using https://minecraft.tools/en/book.php
Overall i have 2 problem, site using "\" for coding book, but mod for creating book need only "".
It's using command block separators like " ' " and it's making error, but fixing this is fast by any repair tool in Json editor.
Can you change it for quality of life?

Another better idea would be to give us the ability to set the book you are currently holding the spawn book.
Say i use https://minecraft.tools/en/book.php to make a book, it generates a command to give me the book. now let me just write /spawnbook set or something to set the spawn book to the one i am currently holding in my hand.