So, what would an actual 'biblical' flood look like ??

[Anomalocaris]

My personal opinion is that the biblical narrative was a local cataclysmic water event in Southeast Asia at the end of the Ice Age, retained in ancestral memory and expressed in flood myths across cultures.

Southeast Asia?

Yes, the biblical land of Cambodia. They do flood there quite often, I was told.

Seriously, the sea level rose 100 meters at the end of the last ice age, and there is evidence part of the rise was abrupt and inundated much of the Asian continental shelf around Indonesia quickly.    The area rapidly submerged parts might have been about the size of Europe.  The problem is abrupt is relative and flooding the sundaland likely took many centuries.

But a more plausible theory for factual origin of the genesis flood myth suggest it was the filling the Black Sea basin near the Fertile Crescent, not the flooding of distant continental shelves, that spawned the cultural memory of great and widespread flood. The basis is the Black Sea became cut off from the Mediterranean Sea when the world's ocean dropped during the ice age. With Mediterranean no longer supplying water the level of Black Sea fell much lower than the global sea level due to evaporation. This freed up large tracks of former sea floor to neolithic settlement. Near the end of last ice age the Mediterranean rose with global sea level and eventually it overtopped the isthmus that separated Mediterranean and Black Sea, this resulted in rapid erosion of the former barrier and very rapid increase in the infill rate at the much lower Black Sea. Within a few month the Black Sea would have been filled to the current level. The Black Sea flood story has the benefit of occurring both closer to then middle east, and can plausibly occur far more rapidly than even the most abrupt sea level change.  It is plausible for the filling of Black Sea basin to occur on the timescale of months.