Is a person considered an unbeliever if they stop praying involuntarily, while remembering the Hadith "The covenant between us and them is prayer, so whoever abandons it has disbelieved," and feeling that they have disbelieved, and then doubts a supernatural phenomenon and believes it based on their feeling of disbelief?

The hadith: "The covenant between us and them is prayer; whoever abandons it has disbelieved" is authentic, not a Quranic verse, and indicates the grave danger of abandoning prayer, classifying it as one of the major sins. However, the preponderant view is that one who abandons prayer does not commit an act of disbelief that expels him from the fold of Islam.

It is obligatory to repent, make up for missed prayers, and maintain them.

It is impermissible to watch programs that include magic and sorcery. What you mentioned about believing it is from the whisperings (waswas) that should not be heeded. You must repent and seek forgiveness.