How to counter argument Ibn khatir's or al tabari's argument about the Quran?

(By the way I am a Muslim myself I just want to know how to counter argument this)

The argument that the Quran both affirms the authenticity of the Torah (Tawrat) and Gospel (Injil) in certain verses, yet also suggests that they have been corrupted (tahrif) over time. The argument often points to verses like Surah Al-Baqarah (2:136) and Surah Al-Ma’idah (5:68), which seem to affirm these books, but then verses like Surah Al-Baqarah (2:79) imply corruption.

What are the best responses to this claim?