Sara has lived in TAiwan most of her life till now. She knows Taiwan as her home. There is no reason she should be forced to leave.
In many countries she could apply for citizenship.
I wonder if she could, as she has been a legal resident for so long?
Maybe she doesn’t want to but wants legal resident rights (and right to work).
They should allow persons who have legally lived in Taiwan (say 8 years or so) the right to acquire citizenship without prejudice to any other citizenship they may carry. Welcome to the 21st century, where many people have mulitiple citizenships TAiwan.
I imagine if she could apply for citizenship without a demand she cancel whatever other citizenship she has, she probably will in her circumstances.