Return to Indonesia citizenship

Hello everyone. I just proposed to my indonesia girlfriend last month, so that's exciting. I didn't realize that indonesia does not allow dual citizenship. I want her to become US citizen and move here to the united states with me. She is unsure and will miss being an indonesian citizen. I tried to research what it would take if maybe someday I pass and she wants to move back to indonesia. It was unclear how someone could regain their indonesian citizenship. Has anyone here done that or known someone who's done that? Does anyone know a person that is a foreign citizen, but lives their life in indonesia? So maybe she could still go back as a us citizen.