What is the ruling on continuing to visit atheistic websites to defend Islam, and is it more virtuous to continue doing so or to devote oneself to worship, knowing that this consumes a long time and causes distress?

It is not permissible for a Muslim who is not equipped with Sharia knowledge to enter the websites of the people of misguidance, lest their fallacies deceive him. Rather, it is obligatory for him to seek knowledge and protect his heart. As for those specialized in Sharia, it is permissible for them to examine these websites to refute atheists and dismantle their arguments, out of a desire to guide them and prevent them from influencing weaker Muslims. This is considered a form of calling to Allah Almighty.