Is Genesis 1–11 Historical or Mytho-History?

Questions about whether Genesis 1–11 is historical or mytho-history, why Jesus referenced people “we know never existed” like Adam and Eve, Noah, and Moses, and whether there’s a method by which we can establish which things we can agree to disagree on.

• Is Genesis 1–11 historical or mytho-history, and aren’t there significant theological implications if the Fall as described in the Bible didn’t happen?
• Why did Jesus reference people we know never existed like Adam and Eve, Noah, and Moses?
• Is there a standard method by which we can establish which things we can agree to disagree on and which things we can’t?