The Saudi government does not recognize dual nationality. Saudi authorities have confiscated the U.S. passports of U.S. citizens and U.S.-Saudi dual nationals when they have applied for Saudi citizenship or a Saudi passport.
This is the same if you are a Saudi citizen and you apply for a US passport. However, US authorities will not seize your Saudi passport. But when you are applying for a Saudi visa you will run into issues with your visa situation unless you have an invitation from MOFA.
Furthermore, if you are an Ex-Saudi national wishing to particiapate in any of the religious visas such as Hajj or Umrah, you will need to apply with the Consulate in person to explain your situation.