Does one who converted to Islam from Christianity receive a doubled reward because they were from the People of the Book, while one who converted to Islam from atheism does not, taking into consideration the atheist's suffering until they came to know God?

The narration about those who will be given their reward twice applies to a believer from the People of the Book who believed in their prophet and then believed in Muhammad, peace and blessings be upon him. This aligns with the verse in Surat Al-Qasas. This is specific to the People of the Book because they know Muhammad, peace and blessings be upon him, is mentioned in their scriptures. However, a Muslim receiving two rewards does not mean they are absolutely better than others. A Muslim who is not from the People of the Book may receive a greater and more abundant reward through their excellence in Islam and their righteous deeds, like Abu Bakr and Umar, may Allah be pleased with them both, who are better and have a greater reward than Salman Al-Farisi and Abdullah bin Salam, may Allah be pleased with them both. Therefore, a Muslim woman should strive in righteous deeds and be mindful of Allah, for she may attain a great reward that could surpass the reward of one who was given two rewards.