AS: "The sun never set over water in ancient Egypt."
Familiarize yourself first with the geography of AE and with their funerary texts, before making such an authoritative sounding, but hopelessly wrong assertion.
Viewed from along the western side of the northern Delta coastline of ancient Egypt, the sun was seen setting into the sea, and from along the eastern side, the sun was seen rising from out of the sea.
"Pepi is the great one, who has come forth to the sky; the Beetle, who has come forth to the [Cool Waters]..........This Pepi is the hill of land in the midst of the *Great Green (waD-wr)." (P 336)
"So, you should go to the sky, for the paths of the (sky's) arcs that ascend to Horus have been swept for you. The heart of Seth shall be fraternal toward you as the great one of Heliopolis, when you have traveled the Winding Canal in Nut's north as a star that crosses the *Great Green that is under Nut's belly. The Duat shall lay down your hand toward the place where Orion (sAH) is, the sky's bull having given you his arm. (P 31)
*note: 'Great Green' (wAD-wr) "The Mediterranean Sea....." (Allen 2005: 431)
Imagine an AE in a little boat in the marshes and myriad waterways of the Delta region during the inundation season - what did they see?
Hint: water, and depending of the height of the flood waters, in some parts, a large expanse of water.
Viewing the eastern horizon from the west shore of the Nile at the western limits of the flood waters during the annual inundation or the western horizon from the east shore at the eastern limits of the flood waters - what did the AE see? - a large body of water - the river Nile in flood.
The eastern shore of the large 'Southern Lake' (She-resy), was about 10 km to the west of Sneferu's pyramid at Maidum, and was connected to the Nile by a waterway. The modern lake is about 40 km from east to west, but in the OK, it was considerably larger. The AE saw the sun, moon, stars and planets apparently rising from out of the waters at the eastern part of the lake which formed the horizon - the boundary between the waters of the lake and the sky.
Now you might begin to understand why the traditional 5-pointed star motif resembles a starfish - why the life of a star begins in the lake / sea - it goes from the water - it flies upwards, out of the sea.......
From the NK book of Nut:
".....Their evils fall to earth and the souls go forth which had fallen to [earth. Their tears drop becoming] fish. [The life of a star begins in the lake. It goes forth] from the [water]; it flies upwards, out of the sea and out of the (previous) form. It is the life of stars. They go forth from the Duat and they withdraw to the sky...." (EAT Vol. I, N&P 1960: 68)
Various lakes and the inundation are mentioned in the Pyramid Texts over 1000 years earlier:
"[When you have emerged] from the lake of life, become clean in the [in the lake of] cool water" (N 348)
"This Unis has come, an imperishable akh, as the one who is to be worshipped (Osiris) who is over the innundation: let the akhs in the water worship him. The one he wants to live, he will live; the one he wants to die, he will die." (W 150)
The king was to be the greatest official of the akhs, the northern Imperishable Stars of the sky (P 467)
Other lakes mentioned in the PTs: God's Lake, Great Lake, Jackal Lake, Lake of Life, Nurse Lake, Shu's Lake, Spread Lake, Stork Lake, Lake of Turquoise......
CT
btw. don't jump to conclusions - when I saw the sun set from my jetty, it did not set in the water - the opposite western shore is not far away enough - it set behind the distant hills, but the red circular disk of the setting sun was reflected in the waters of the lake.