It may be a good idea to start the book with a really short "About the author" to state exactly this and your work experience. Otherwise looks well written to me, good job! :)

Native English speaker. I scanned it and IMO there's a slight overuse/misuse of hyphens. Maybe the AI tool could be asked to identify and correct? (The hyphens might be triggering people to think it's AI, too).

They mostly need replacing with a full stop or a colon.

E.g.

"In practice this means storing the amount as an integer in its smallest unit - €12.34 becomes 1234"

->

"In practice, this means storing the amount as an integer in its smallest unit: €12.34 becomes 1234."

or

"In practice, this means storing the amount as an integer in its smallest unit (e.g., €12.34 becomes 1234)"