Is the residence of Muslims in the lands of the disbelievers considered a sin, especially for those who were born there and find no way to move to Islamic countries?

The summary of the fatwa is that residing in lands of disbelief (Kufr) falls into two categories:

The first category: Prohibited residency. This is when a Muslim cannot guarantee the safety of their religion, meaning they lack sufficient knowledge and faith to remain steadfast in their religion, or they cannot openly practice their religion, or they are unable to perform the rituals of Islam, or they show loyalty to and affection for disbelievers. In this case, emigration from these lands is obligatory.

The second category: Permissible or recommended residency. This is when a Muslim can guarantee the safety of their religion, and can openly practice their religion and perform its rituals without hindrance. This residency can be recommended if it is for the purpose of inviting others to Islam and spreading goodness, provided that the da'wah (invitation) can be carried out and there is no obstruction to it.

Nevertheless, the surrounding environment remains a danger to the Muslim and their children. Muslims there must cooperate to create a sound environment and establish da'wah centers to educate their children. And Allah knows best.