Thus Israel's redemption is presented here as a function of the desecration of Hashem's name. God will redeem His people irrespective of their repentance, in order to bring an end to the desecration of His name by the enemies who associate Israel's downfall with Hashem's perceived weakness. We might point out another significant difference between the Torah and the Song. The Torah sections concerning the covenant, Ki Tavo and Nitzavim, speak of choices. In contrast, the Song of Ha'azinu describes sin and redemption in almost deterministic terms.
Human choice seems to be removed from the equation.
It seems to me that two possible approaches are possible. In the more straightforward approach, we might say that in fact there are two possibilities concerning redemption. The Torah would thus be describing the first possibility, and Song the second. On a more profound level, we might view the two versions as presenting two forms oDivine providence. According to our limited frame of reference, these two seem irreconcilable, but from the perspective of the Absolute Intellect they are the same.