Why was it mentioned in the noble Hadith that one of the days the Dajjal will stay is like a Friday, even though Friday is like any other day? And is what is meant by it "like a week"?

The intention behind "Jumu'ah" in the hadiths is "week." This is a case of naming a whole by a part, as mentioned by linguists and commentators on hadith (definition). Al-Harari explained that "Jumu'ah" in the hadith means "week." An example of this is Muslim's hadith: "Indeed, the people of Paradise will have a marketplace which they will visit every Jumu'ah," meaning every week. Muhammad Fu'ad 'Abd al-Baqi commented that the meaning is "in the span of every Jumu'ah, i.e., a week." Similarly, in another hadith from Muslim: "The deeds of people are presented every Jumu'ah twice: on Monday and on Thursday..." meaning every week.