Is it permissible to supplicate with, "I ask You to subjugate for me, from Your noble angels, whoever will avenge me against this rebellious impediment that obstructs me from time to time; indeed, You are over all things competent"?

There is no objection to this supplication as long as it does not involve a reprehensible transgression. Nevertheless, the comprehensive prophetic supplications are better and more deserving, because the Messenger of Allah, may Allah bless him and grant him peace, used to prefer comprehensive supplications that combine the good of this world and the hereafter, having few words but great meaning, such as His saying, the Most High: {Our Lord, give us in this world [that which is] good and in the Hereafter [that which is] good and protect us from the punishment of the Fire} (Quran 2:201).