Hi globell,
Re: "Can I move my book from a Pages Apple Book Template to another format to sell my book on Amazon, Kindle, etc?"
Seems, in the Pages app itself, you would be able to use File > Export to ... and choose EPUB format.
The EPUB book may or may not retain your exact measurements, so it is wise to keep a copy or two of the original Pages book file handy for safe-keeping. (Eg: File > Save and / or File > Duplicate)
You may need to check with publishers about their particular requirements, yet EPUB is the generally used book format.
See Apple support's online article (link below)
Intro to creating a book in Pages on Mac - Apple Support
Eg: says:
"Books in EPUB format can be opened in Apple Books and other ebook readers".
"When you’re ready to view or share your book, you export it in EPUB format.
In the export dialogue, you can add the book title and author name, choose a cover and more.
You can send the book to someone else or view it in Apple Books".
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Else: Seems you don't need to export to EPUB first if you optimise your book for publication in Apple Books.
More info: Publish a book to Apple Books in Pages on Mac - Apple Support
Useful resource: Pages User Guide for Mac - Apple Support
All the best! :-)