One way to look upon the Hyborian Age is as Mytho-History.
A fusion of what is known (or speculated, keep in mind Howard wrote with the understanding of an enthusiast during the 1920s, the study of history and archaeology has advanced by leaps and bounds since then) and what is folk lore or mythology. This allows one to use places and people with familiar names while invoking fantastical elements. Romance of the Three Kingdoms is another example of Mytho-History, if you wish to look internationally.
In the Hyborian Age, there is no Mediterranean Sea. Instead, the river Styx (read:Nile) winds all the way to the Ocean. There is quite a bit of geological evidence for a time when the Mediterranean basin was not filled. However, it is not generally dated as a time when humans did much of anything. See: Zanclean Flood if you are curious.
Howard himself places the Hyborian Age between the Sinking of Atlantis and the beginning of recorded ancient history. This is awkward as Atlantis was explicitly made up as a fantasy land for Plato to describe crappy governance (see: Timaeus and Critias) and recording of history started at different times in different places.
However! He actually hits a large number of Eastern Mediterranean/Fertile Crescent points head on. Our knowledge of life before the Bronze Age Collapse is limited. However, the rare use of Iron is noteworthy. Iron is much harder to work than the myriad Bronze Alloys, and not (in it’s early stages) universally superior to work hardened bronze. Both Iron and Copper are not terribly useful in unalloyed forms (for the needs of the 5 millennia ago). The formulas for mixing Copper and Arsenic, Tin, and Nickel were quite well documented. However, the method for making steel (much less getting a furnace hot enough to smelt iron in the first place) were not. Typically, Iron saw use amongst isolated Mountain persons who were not associated to the Imperial City-States of the time. Except when the City-States wanted prisoners with jobs. But that standard of the “Barbarians” being the ones with the “Riddle of Steel” actually holds more historical weight than one would imagine.
Also, it is important to note that we have solid evidence that Norse people were trading with (what is now) Egypt before the Bronze Age Collapse. (To say nothing of the trade empire in what is now North Western India, which went dark all of the sudden and may have triggered the collapse in the first place, with the Sea People rolling in to nail the coffin lid down) So the world was reasonably interconnected. Pirates were a major factor, one of the two distinct and solid causes of the collapse were a Pirate Armada savaging the Eastern Mediterranean.
Ok, Imma gonna stop there before I revisit the most recent lecture I gave in it’s entirety.
TLDR; Mytho-History is what we get if we assume all the superstitions and fables were true at least on some level, and reinterpret history based on those specific events and standards. It’s ubiquitous and an excellent way of creating something both recognizable but also filled with wonder.