How can one get rid of the feeling of envy and avoid blaming oneself for causing harm to others, especially when something bad happens to them after one has wished for the cessation of a blessing?

Envy is forbidden in Islamic law due to the established prohibition in the Hadith (definition) and Allah's saying: "Or do they envy people for what Allah has given them of His bounty?" (Quran 4:54). Therefore, you must repent to Allah and cure yourself of this illness. Remember that the distribution of provisions is in Allah's hands, so be content with His decree and destiny. Know that what was meant to befall you could not have missed you, and what missed you was not meant to befall you. You must also lower your gaze from what others possess, in accordance with Allah's saying: "And do not extend your eyes toward that by which We have given enjoyment to [various] kinds of them - the splendor of worldly life." (Quran 20:131). If you see something that you fear might be afflicted by the evil eye, supplicate for blessings and say: "Masha'Allah, la quwwata illa billah" (What Allah wills, there is no power except with Allah). If you know that you have afflicted someone with the evil eye, perform ablution for the afflicted person, repent to Allah, and seek forgiveness from the one you have harmed.