Thanks for the added context. I’ll look into comedy or parody films that involve mysterious or cursed TV channels, possibly with names like “Channel X” or “Signal D,” and feature a paranoid, tinfoil-hat-wearing character. The tone you described—satirical and ‘fake serious’—will be central to the search.I’ll let you know once I’ve tracked down possible matches.
The Signal (2007)
The clues all point to the indie sci-fi/horror film The Signal (2007). In this anthology movie, every TV/radio transmission emits a mysterious signal that drives people insane and violent. As Wikipedia describes, in The Signal “all telecommunication and audiovisual devices transmit only a mysterious signal turning people mad and activating murderous behaviour”en.wikipedia.org. The film is presented in three parts (each directed by one of the filmmakers), and notably its second chapter is explicitly a black comedy about conspiracy paranoiaen.wikipedia.org. This matches the question’s description of a satire that is “stupid but filmed to fake serious,” spoofing the trope of harmful broadcasts (à la UHF, Bad Channels, etc.).