The Egyptian religious record is enormous and it is skewed in a way that is easy to state and hard to correct for. Tombs and temples were built of stone on the desert margin because they were meant to last. Houses, villages and the ordinary business of religion were built of mud brick on the floodplain, where the annual inundation and later cultivation have removed most of them.
The result is that Egyptian religion is known overwhelmingly through funerary material belonging to people wealthy enough to be buried well. The great compilations, the coffin texts and the collections of spells that became the Book of the Dead, are guides for the dead of a particular class. What an ordinary household did is reconstructed from a much thinner record, and the workers' village at Deir el-Medina is disproportionately important simply because it survived.
There is also a long interruption in understanding. Knowledge of the script was lost in late antiquity, and for roughly fourteen centuries Egypt was read through Greek and Roman authors and through a European tradition that treated the hieroglyphs as mystical emblems rather than as writing. Only with the decipherment announced by Champollion in 1822, working from the Rosetta Stone, did the texts begin to speak for themselves.
Much of what circulates as ancient Egyptian wisdom today descends from the pre-decipherment tradition rather than from the texts, and the two should not be confused.