The change of the supreme god to the Aten by Akhenaton was not the first time that there was a change in godhead in Kemet.
In hermopolitan tradition, Amon was king of the ogdoad. In thebes, he became king of the gods Amon-Ra.
In heliopolis tradition, Atum was supreme god of the ennead.
Different gods were worshipped in different regions.
I think Akhenaton was trying to have Kemetic people under one banner by worshipping one god instead of different gods in different cities.
Also, Akhenaton did not destroy the worship of Hapi because it was hapi that caused the nile to overflow leaving fertile soil to grow crops.
Personally, I think people who later saw the ruins of Tell Amarna and things like "Hymn of the Aten," made the Aten into God/yahweh and Akhenaton into Christ. Check how close the hymn of the aten is to psalm 104.
It was not Akhenaton who did that. He had been long dead.
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