Don't worry about the immensity. Christian theology has grappled with "free will" for ages, and after fruitful engagement with modern philosophy, Christian philosophy has produced a logical and realistic account of the phenomena of "free will" in human souls.
By the way, the most likely interpretation of the quote (as explained in this Philosophy.SE question) is
"you are free to do whatever you desire, but you are not free to choose your desires"
Christian theology concurs with the above by appealing to empirical data that it's very easy to assent to follow our desires, good or bad, but especially bad ones. Christian theology teaches that our free will is BROKEN, biased to do what we know to be wrong. Most groups agree that since we are born our will is dominated by concupiscence which hijacks our attempts to do good. Paul talks about this in Romans 7:14-25. No one will dispute the fact that all humans are "enslaved" by self-centered desires ("not free"), unless they exert extra effort to overcome them. Sometimes natural love makes it easier to wish the good for others (children, lovers, etc.) and then to actually do the good acts, but we all realize it's not sufficient sometimes.
But please understand punishment correctly. In Christian theology, God punish us for the sinful ACT (fruit of the will), but NOT usually for the WILL per se, especially if we are fighting our own desires which induce us to will harm. Even if we succumb to sinful acts or to "sins of the heart" (like cursing others, lust, or envy), the punishment is mitigated by many factors that are "straitjacketing" the will such as addiction, ignorance, biological factor, passion of the moment, history of abuse, etc. People of goodwill recognize that they did wrong (the Catholic formula is "in my thoughts and in my words, in what I have done and in what I have failed to do") and would be induced in their conscience to confess their sins in front of God and to cry out for deliverance of their broken will. God (out of his abundant mercy) will forgive the sins and (upon request) will infuse grace to strengthen their will so they can potentially succeed when they try again.
Some Christian philosophers such as Eleonore Stump proposes that the will has three positions, not two: assent, rejection, or quiescence. Even though our will is broken, we can at least opt for "quiescence", the posture that allows God to strengthen our will by grace (i.e. increasing our love). This is God's way of preserving our free will; God will not force his grace on us. See this paper Grace and Freedom: Examining Stump's View of the Quiescent Will.
Christianity teaches that we cannot "assent" to heal our own broken will ourselves since we are trapped in the conflict of wanting to love and don't want to love at the same time. We need God's supernatural assistance which God offers unilaterally but which we are powerless to positively "assent" to receive it (because of this conflict).
But by freely putting our will in "quiescence" setting instead, we can acquiesce ("cease resisting") to receive the needed grace to fix our broken will. In this video, Eleonore Stump likens it to a child agreeing to receive a vaccine injection where the child neither rejects nor positively desire the vaccine (how many child says "please give me a vaccine?"). God only punishes us when our will is in the "rejection" setting (i.e. refusing the gospel when it is fully understood), thus refusing God's grace that could have assisted us in wanting to want to love (second order will) so we are put in the process of growing to want to love and be loved (first order will).