What is the way to get rid of doubts related to the existence of God, the truth of Islam, and some unseen concepts such as jinn, in addition to some Sharia rulings like killing an apostate, all of this after visiting atheistic websites that affected one's faith?

It is recommended to completely refrain from reading the words of atheists and to strive to get rid of their residues by turning away from contemplating them, because the probability of coincidence in the creation of the universe is weak and has become a cause for ridicule. The place of guidance is the heart, as modern science has proven that it thinks, perceives, and transmits information to the brain. Islam called for contemplation of God's creation, not the unseen, because creatures are perceived by the senses, and the unseen cannot be comprehended by reason alone. To answer the question: "Why does Islamic law kill one who leaves Islam, when Islam guarantees freedom?" Please refer to Fatwa No.: 122412. The questioner does not need scientific responses as much as he needs God's help and guidance, and is advised to ponder the Quran, continue reciting it, frequently remember God, and supplicate persistently.