Why do the Quranic verses speak of the sun's setting and rising in the story of Dhul-Qarnayn, instead of the earth's west and east? And what is the correct interpretation of "a murky spring" and "a people for whom We had provided no covering apart from it"?

A Muslim should pray to Allah and strive to seek knowledge from well-grounded scholars when encountering difficulty in understanding a verse, and refrain from delving into the Quran without the proper means. The majority of exegetes have interpreted the verse to mean that Dhul-Qarnayn reached the furthest inhabited land from the direction of the West, where he saw the sun setting in a murky spring, meaning dark with water and mud, or in the encompassing ocean. This is from the perspective of the naked eye, not that the sun literally entered the earth, for it is much vaster than the earth. This does not contradict any scientific fact.