Is it obligatory to delete channels specializing in songs, series, foreign films, and the like, or is it sufficient to leave them for the viewer to bear their sin alone? And does sin befall whoever leaves channels that broadcast mixed content, including series, films, and songs?

You did well in removing the objectionable channels, and this is your duty as a guardian, based on the Almighty’s saying: "O you who have believed, protect yourselves and your families from a Fire" (Quran 66:6), and the Prophet's (PBUH) saying: "Each of you is a guardian and is responsible for his subjects."

As for channels that mix good with evil, there is no harm in keeping them if it is possible to benefit from their good and avoid their evil. If this is not possible, such as when family members become lax in watching the content, then they must be removed if access to them cannot be controlled with a password to benefit only from the permissible content, in accordance with the Almighty’s saying: "And cooperate in righteousness and piety, but do not cooperate in sin and aggression." (Quran 5:2).