In academic works or projects, 5% plagiarism is permissible; anything above 5% is considered plagiarism and is not accepted
I've never heard of that 5% rule. If you write an article about Bitcoin mining, chances are at least 5% of the words are also used by someone else who write an article about Bitcoin mining. And that's fine.
But if you write 10 pages and copy half a page from someone else, that's not good.
I want to really understand something here, are you saying that someone who is writing an article about bitcoin mining and draft out like half of the article by itself and the completion of the work happened to be four lines stanza from someone's work that has be done initial or previously without adding the reference source, is not a plagarism? We are here to learn.