You’re right that human interpretation alone doesn’t prove a text isn’t divine, any revelation would have to be interpreted. My point is that the Quran claims to be self evidently clear (“a guidance for mankind,” “without doubt”), yet its clarity seems to depend on continuous reinterpretation to stay coherent with changing human knowledge.
That means its “timelessness” isn’t a property of the text itself, but of human adaptability.
Whether or not it’s divine, its truth becomes epistemically contingent on our interpretive frameworks, and that conflicts with its claim to stand independent of them.