Is it authentically established in the Prophetic Sunnah that the supplication: "O Allah, deal with us according to that which befits You, and do not deal with us according to that which befits us, for You are worthy of awe, and worthy of forgiveness," is beloved to Allah?

The supplication "Our Lord, deal with us as befits You, and do not deal with us as befits us" was not narrated in the Sunnah. However, it was reported that the people of Yunus supplicated with it. There is no harm in supplicating with it, as it is not a condition for a supplication to be from transmitted texts. Rather, it is a condition that it be free from any Sharia prohibition, so the servant will not be answered if he supplicates for a sin or the severance of kinship ties.