How can one escape the cycle of overthinking and self-blame after an unintentional accident led to the death of a child? And is this a punishment or a trial from Allah, knowing that I am committed to my religious duties and obligations?

It is advisable to turn the page on the past and forget the incident, avoiding excessive self-reproach that leads to despair and despondency, for grief is from the work of Satan. What helps in overcoming this is remembering the vastness of Allah's mercy, and that Allah accepts the repentance of one who sins intentionally, so how much more one who errs unintentionally, as Allah Almighty says: "And there is no blame upon you for that in which you have erred, but [only for] what your hearts intended. And ever is Allah Forgiving and Merciful" (Quran 33:5). Also, reflecting on the harm of despair and despondency, and seeking Allah's help. The knowledge of whether the incident is a punishment or a trial is with Allah. The questioner is cautioned that the statement "I perform all my obligatory duties and responsibilities" may suggest self-praise, which is not characteristic of a believer. Repentance from abandoning commanded good deeds is more important than repentance from committing bad deeds, and a servant is deficient no matter how hard they strive, and must seek forgiveness and repentance after every act of obedience.