In using Old Testament figures for comparisons, the authors of the New Testament considered each of them as historical as the next. Adam, Noah, Abraham, Jonah, Moses, and David were each real people who lived and died on this earth as the Old Testament speaks of them.
[1Co 15:22 ESV] 22 For as in Adam all die, so also in Christ shall all be made alive.
[Mat 24:37 ESV] 37 For as were the days of Noah, so will be the coming of the Son of Man.
[Gal 3:6-7 ESV] 6 just as Abraham “believed God, and it was counted to him as righteousness”? 7 Know then that it is those of faith who are the sons of Abraham.
[Jhn 3:14 ESV] 14 And as Moses lifted up the serpent in the wilderness, so must the Son of Man be lifted up,
[Mat 12:40 ESV] 40 For just as Jonah was three days and three nights in the belly of the great fish, so will the Son of Man be three days and three nights in the heart of the earth.
[Rom 4:5-6 ESV] 5 And to the one who does not work but believes in him who justifies the ungodly, his faith is counted as righteousness, 6 just as David also speaks of the blessing of the one to whom God counts righteousness apart from works:
Assorted liberals, theistic evolutionists, and old-Earth creationists will draw their own line at who they believe were historical figures. They might consider David and maybe Moses to be historical. Abraham’s existence they more likely think is a stretch, but Jonah, Noah and certainly Adam (they say) definitely did not exist. In all of this they have departed from the Scriptures and made their own considerations the standard. And in doing this, they detract from each of the doctrines of the New Testament where comparisons to these figures are made.