It’s usually been thought of as near Cadiz; a port city on an island in the river.
An earthquake more or less leveled it.
That’s the area this Brit firm is looking at:
“Experts at Merlin Burrows believe the flooded ruins of the legendary city are off the coast of southern Spain.
“The location is somewhere north of the city of Cadiz, Andalucía, centred around the Doñana National Park, which the historians believe was once a vast inland sea.