My position on such matters as what Paul thought was historically true and not true is that Paul also believed - - is there any doubt of this?!?! - - that stars could fall to Earth without doing Terrifying damage at all to Jupiter and Mars - - let alone Earth.
And yet, we know such is preposterous. Paul, and even Jesus, were trapped by their mortal minds into sharing many of the non-scientific views of their families, teachers and everyone else in the Ancient world.
Should we not conclude that Paul’s interest in Adam’s historicity is ultimately what God intended? - - that it be an interest ultimately based on allegory?