Personally, I feel that this situation is not plagiarism.

First, you just extract paragraphs; The second and third paragraphs are only 500 words; Third, the paper is allowed to quote other articles.

The most important thing about plagiarism is that the ideas and arguments of the paper are not formed by learning something. The trunk part belongs to someone else.

Collecting arguments and explanatory materials for one's thesis is not plagiarism. The argumentation of the paper needs a argumentation process, arguments and explanations. Where did these come from? Of course, I have to extract and quote other articles.

So your situation is not plagiarism.

Note: This is my personal opinion for reference. I'm not a professional in this field.