Is watching television, specifically the series "Sanawat al-Dayya'" (Years of Loss), which contains no nudity, forbidden and the reason why the questioner does not feel the sweetness of faith, even with lowering one's gaze from the men in it?

Most TV series are not free of unlawful content. If they are, then there is no harm in watching them, as long as it does not lead to neglecting duties. The lack of feeling the sweetness of faith might be due to watching TV series that contain unlawful content, for faith increases with obedience and decreases with disobedience, which darkens the heart. One can follow alternative Islamic channels that offer educational programs, useful games, and permissible entertainment.