I have a soft spot for such folklore. Strictly speaking, much doesn't hold up to scrutiny but I see no wrong with wild conjecture for the fun of it.
For starters, some catastrophes do shine through more recent history:
- https://en.wikipedia.org/wiki/List_of_flood_myths
- https://en.wikipedia.org/wiki/Volcanic_winter_of_536
- https://en.wikipedia.org/wiki/Year_Without_a_Summer
Then, Nuclear Evangelism is a fun idea, proposing a religion teaching us to stay away from nuclear waste for 10k years: https://www.nahomatsuda.com/nuclear-evangelism
Or you can poke around linguistics
- https://en.wikipedia.org/wiki/Historical_linguistics
- https://www.deadlanguagesociety.com/p/does-your-name-belong-...
The Arthurian legends and Robin Hood are two English-speaking examples of folklore snowballing into what we have today. I bet James Bond will join them in a few hundred year's time.
You are mixing up a lot of timelines (mostly in AD) and hence not a good comparison.
I am talking about records from 5000-7000BC (deducing from Sanskrit literature) by which time they had already been orally transmitted for eons. So they are truly ancient with layers upon layers of grafting of realities/myths/stories over time.
There is nothing in Sanskrit literature that securely old. The Vedas already postdate the mixing of Indo-European speakers and the people of the Bactria-Margiana Archaeological Complex, and we know that was much more recent than the fantastical ancient dates that are passed around laypeople in India.