plagiarism does NOT refer to copying the work of another author, it refers to you submitting work as yours that you didn’t yourself write.

if I copy entire article from the Economist, did I plagiarize!? There is no author attribution so we don’t know the author… Many articles in media today are LLM generated (fully or partially), can I copy those if someone sticks there name as author?!

bottom line is - you didn’t do the work but copied it from elsewhere, you plagiarized it, period