To be clear its not like the people who established these kingdoms came to back to somalia and that we descended from those people. Its more like the relationship between American and britian. A huge amount of America's culture and ancestry traces back to britian.I don’t believe that Somalis descend from these people, but I believe that our ancient ancestors and the founders of the Old kingdom had the same origins but we split off.
The oldest depiction of boats in ancient eygpt for example come from wadi hammat and date back to 4000 b.c