It would be very interesting to implement the use of this type of verifier in our anti-plagiarism unit. Thanks for sharing.
As you have said, determining plagiarism can often be difficult. Except for vulgar plagiarism of those who make a full copy / paste (including images) of the article.
The nature of the article also influences the percentage of use of quotes.
Maybe you know any content verifier based on AI? I would consider it to be of a high level of reliability.