There is no "fundamental" version of these myths. In many cases (particularly with Norse mythology) all we know is what was written down by Christian scribes, purposely redacted to fit a Christian worldview. Modern Neopagan ideologies necessarily have to differ because of the dearth of original sources from which to reconstruct the religion, and because neopaganism in modernity would be inextricably linked to modern political, cultural and moral norms (as any religion in any age would be.)

[0]https://en.wikipedia.org/wiki/Neopaganism_in_Scandinavia

[1]https://en.wikipedia.org/wiki/%C3%81satr%C3%BA