What is the ruling on having two different names in two different countries to obtain material and in-kind privileges (citizenship, salary, housing) in each country, and how should one act in such a case?

Affiliation to another father is forbidden because the Lawgiver has prohibited a person from claiming a lineage other than their original one. Whoever does so is forbidden from Paradise, and it is an act of disbelief, incurring the curse of Allah, the angels, and all mankind. This act also involves deception and lying, and the Prophet, peace and blessings be upon him, said: "Whoever cheats is not one of us."