The repeated noun instead of a pronoun
Hypothesis examined: when the Qur'an repeats a noun where a pronoun would do, it would be to isolate each occurrence and give it its own weight.
The starting fact is real. In 114:1-3, "mankind" occurs three times in a row: "Guardian of mankind, Sovereign of mankind, Deity of mankind", whereas Arabic could have said « مَلِكِهِمْ » ("their Sovereign") after the first mention.
But the hypothesis does not merely state that the noun is repeated: it claims why ("to isolate each occurrence"). No examination of the text can confirm or refute that reason. One would also have to show, case by case, that a pronoun was possible at each point, which the hypothesis does not do.
What matters for translation is already covered elsewhere: a repetition in the text is kept as it is and is not replaced by a pronoun (see “The repeated formula: same Arabic, same translation”).
In the text
بِرَبِّ ٱلنَّاسِ مَلِكِ ٱلنَّاسِ إِلَٰهِ ٱلنَّاسِ