https://en.wikipedia.org/wiki/Doggerland
You could walk from the Netherlands to Britain.
Before that, the Mediterranean Sea was a dry depression. When the Atlantic barrier collapsed, you can imagine the wall of water filling the basin and chasing early humans uphill.
Some think the Black Sea was much smaller, and filled up, during the period in question. But evidence there is inconclusive.
We know there was a cataclysmic meteor strike toward the west end of the Persian Gulf, well after it had filled in.
Evidence of catastrophic flooding is debated and inconclusive.
That the black sea’s level used to be much lower is not, all water levels were much lower at the glacial maximum, and gradually rose as the ice age ended, nearing stable historical sea levels around 7.5kya (5500 bce).
But the subject is complicated by the unknown inflow from rivers, and from meltwater of retreating glacier.
Hydrology is complicated.