I am in 9th grade and am working on a class project on T’shuva. Was there one person in the Torah who personified T’shuva? What did he/she do?

There is no explicit mention of anyone who did Teshuva in the Torah, whoever our sages listed several figures from the Torah that have done Teshuva, here are some: The Midrash [Raba Bereshit 22] comments Cain did Teshuva for killing Abel by confessing and regretting the crime. The Midrash [Tanchuma Shmot 15] notes Terach, Avraham's father did Teshuva. Yishmael is known to do Teshuva before Avraham passed away [Bava Batra 16b] Levi did Teshuva for the Shchem incident – the Torah he studies and taught atoned his sin. Reuben fasted since the Bilha incident and his Teshuva was accepted [Midrash Hagadol Dvarim 6:4] Yehuda confessed Tamar's child was his and merited the word to come [Sotah 7b]