Is it true that a female admirer might fall into shirk (polytheism) without realizing it, because when she recites Al-Fatiha and thinks of her beloved, the pronoun in (You [alone] we worship and You [alone] we ask for help) refers to her thoughts of the beloved in her heart, which could lead her into shirk?

What is called admiration or love is often among the sins and transgressions related to abnormal instinctive lust, and not among the doctrinal sins. Therefore, it is judged to be forbidden, and it is not considered polytheism unless the admirer reaches the point of believing in his beloved what is not permissible to believe in a created being, or attributing divine characteristics to him, which is unlikely for a Muslim. As for someone who directs the pronoun of majesty "You alone we worship" to his beloved or addresses him with it, he is a major polytheist who exits the fold of Islam. However, merely thinking about the beloved while reciting the verse does not cause its meaning to be diverted to him.