There were definitely more cities which were coastal that disappeared as soon as the sea level rose several tens of meters.
Fishermen have been pulling up housing remnants, bones, fishhooks, etc for a long time out of there.
Australia too: https://www.dailymail.co.uk/sciencetech/article-8479739/Firs...
There's a bait-and-switch happening here.
It should be easy to see how being forced to leave your ancestral home would transmute, in the telling over millennia, into a cataclysmic event.