In my view, pyramids are manifestly associated with the sun, though the 6th dynasty royal tombs were specifically formulated to incorporate texts, the pyramid shape and size by that time had become more or less iconic in nature rather than practicable as it was during the 3rd and 4th dynasty's. As it was, we can clearly see the evolution of the texts during the Old Kingdom, and the furtherance of them through coffin texts and book of the dead texts. That these variants can be traced back to Unis's burial chamber (some even earlier) demonstrates how fluid their ability was to expand them, after all they were spells--magic. Clearly, the afterlife cults of the 4th and 5th dynasty evolved to a point that by the sixth dynasty Nut, Osiris, Isis were promoted and Anubis, Sokar, Hathor were summarily absorbed. On these merits we should understand that ritual afterlife practice had vastly expanded and morphed by the time of Pepi I, and though the sun was eternity, reaching that place became so much more involved.

Best,

B.A.Hokom