Help me build a futtter-based ebook and audiobook reader app

I am author with sevral books, ebooks and courses.

I am looking for flutter/dart app developer to help me make this a reality.

I want to buy scripts/code on marketplace and have it finalised.
I would to create an ebook/audiobook app in flutter


I prefer a singular designer, not an agency.

I am willing to buy code from code canyon and need help with customization and publishing.

What I need help with is:

choosing the right code template to buy.
Adding a paymant gateway
Preventing copy+paste and also screenshooting.
Incorporating admob.
adding comment and reviews section to the books

If you have already build an app in flutter, please share a link.