As I understand:
1 - The gods were created by the engwithans.
2 - The engwithans were the previous settlers of Eir Glanfath, in the Eastern Reach.
3 - The Eastern Reach was discovered in 2602 by explorer of the Aedyr Empire, 223 years before the start of PoE 1.
4 - The engwithans lived in the Eastern Reach thousands of years ago, so their gods and cults were spread all over that continent.
5 - Readceras was an aedyran colony where Eothasian colonist settled in 2643.
6 - So, Eothas was (is) an aedyran god.
So:
1 - Was (is) Eothas a god not created by the engwithans?
2 - If that's the case, who created it?
3 - Were the gods transcontinental although the Eastern Reach did not have knowledge of Aedyr Empire before 2602?
4 - Did the engwithans lived where the Aedyr Empire is located?
5 - If that's the case, how the two continents didn't have notice of each other?
6 - Were the aedyran gods of a different nature?
My sources are a mix of in-game books, the journal of the Watcher and the wiki.