This answer can be answer looking from the society/cultural aspect.

Egypcians had hieroglyphic writing since at least 3000 B.C. Now having writing doesn't guarantee that you nation deeds and goodness and day to day feets will survive the eons of time. For example there is no historical record from Alexander The Great or the Greco/Bacterians states from the Indian perspective as they were lost in time.

Egypt has a big advantage in terms of their records as that, they have many writing surviving to today as a huge amount of stone with hieroglyphs survives until today. Keep in mind that this wasn't totally until the discovery of the Rosetta Stone (1799), which gave the key to unlock many words and the logic of how hieroglyphics could be read.

Norse/Germanic people that followed the "Norse Pantheon", few sources of information comes from a few Raisestones. All the accounts that survive from "Vikings Age" are mostly from Christian monks which are the few who could read/write. Which meant that usually they were the victims of a raid, or attacks and not very prone to writing about anything other than the brutality and savagery observed. Because of this usually in this paradigm Christianity is linked to the only latinized source of information that we have about vikings (Note: This only refers to the start of the viking age 700-900, as after this point vikings started to slowly convert into christianity, but sadly there is not many sources detailing norse pantheon and stories)