Is the aforementioned Hadith from Abu Hurairah authentic, and is it permissible to supplicate with it, and if permissible, how should its words be vocalized?

The Hadith is authentic, and cursing is forbidden. Imam Muslim narrated it with the wording: "O Allah, I take a covenant with You which You will not break: I am but a human being, so any believer whom I have hurt, insulted, cursed, or lashed, make it for him a prayer, a zakat, and a means of proximity by which You bring him closer to You on the Day of Resurrection." No one other than the Prophet, peace and blessings be upon him, has a covenant that his cursing transforms into mercy. His supplication that turns into mercy refers to those who were not deserving of his supplication against them or were not intended. The Prophet, peace and blessings be upon him, was compassionate towards his Ummah. Cursing a specific individual is forbidden, but cursing disbelievers in general is not forbidden. A believer should not be given to cursing, and cursing a believer is like killing him. If a servant curses something, the curse ascends to the heaven and then returns to the earth; if it finds no place, it returns to the one who uttered it.