The ancient israelites wrote about a legendary jungle area between dried up due to human activity affecting the climate south east of the present day shores of the remaining rivers
Which jungle?
And what rivers?
Do you mean the rivers mentioned in Genesis 2?
If so, then Pishon & Gibon don’t exist. Havilah, where Pishon surrounded it, and include where gold, onyx & bdellium were found, also don’t exist.
While the land between Euphrates & Tigris point to today’s Iraq, there were never rainforest let alone a jungle in the past or present.
Mesopotamia proper is surrounded by arid regions, there were never forests in this region, even during the Neolithic period (11,000 to 5200 years ago).
Move to the upper region, where Euphrates & Tigris begin to flow from, from the Armenian Highlands, which are more fertile than Mesopotamia, it is the steppe, hence mainly region of grass and shrubs, not a place that one would call “jungle”.
What Genesis tells me, the author(s), whoever wrote Genesis, doesn’t really have great knowledge of west Asia.
You might called Havilah & Pishon, and the Gibon, “legendary“, but I certainly would put these places as more mythological than legendary.
Including the mythological, are the Garden of Eden, Land of the Nod, Enoch (city supposedly built by Cain)…they don’t exist except in a story of “Creation”.