Is there any objection to a girl preferring anime characters to real boys, and can she have anime children in Paradise due to her suffering from frigidity?

There is no need to worry. Your interest in anime characters may be a way for you to develop an interest in real children in the future. Hasten to marry. A woman can search for a husband or offer herself to whomever she desires, while observing the Sharia guidelines. Sexual frigidity is not an impediment to marriage and may disappear after it. Seek help through supplication (du'a), ruqya shar'iyya (Islamic exorcism), and a trusted female psychiatrist. Let Paradise be your ultimate concern, for in it is everything the souls desire: "They will have therein whatever they wish, and with Us is [in addition] more" (Quran 50:35), and "I have prepared for My righteous servants what no eye has seen, no ear has heard, and no human heart has conceived."