What should one do if they find themselves unintentionally envious in a way that harms others, and experiences internal cursing and insults, even against the Divine Self, the Prophetic, and Islamic values, despite these matters being automatic and involuntary? And what is the sin resulting from that?

A person's awareness of what might come from them is a good thing, as long as it doesn't reach the level of obsessive doubt (waswasah). Regarding unintentional envy from the evil eye: the one who cast the evil eye should do what is mentioned in Fatwa no. 42640. If the affliction does not go away, there is no blame on them, and perhaps it is a trial from Allah for those affected. As for cursing others to oneself, there is no sin, even if it reaches the level of blasphemous thoughts, for there is no accountability for them, Allah willing, as long as the person does not speak them aloud or act upon them. As for distress and desolation, they are dispelled by repentance, general obedience to Allah, and supplicating to Him.