I think the Oath of Allegiance should be modified to include renunciation of all allegiance and fidelity to legal systems incompatible with the American system of government.
I can go with your suggestion/idea as to putting a real/pointed obligation to forsake all/any other for the US Founders and Their Constitution into the Oath of Allegiance. I don’t believe anyone adhering in any way to Sharia law would pass the requirement. Send all such persons out of the US to any part of the world where they can practice such duplicity.