Is there anything reported in the Sunnah of the Prophet, peace and blessings be upon him, that proves "Al-Jathum" is a jinn that sits on the chest of one who abandons prayer, or is this a superstition?

Al-Jathum is the nightmare that afflicts a person during sleep, also called Al-Khaniq (the strangler) or Al-Naydalan. In it, the afflicted person feels a heaviness weighing down on them, shortness of breath, and an inability to speak or move. This is a reality, not a superstition. Al-Jathum can be due to physical factors such as the effect of food, medicine, or psychological pressures, or it can be due to the dominion of jinn. The treatment for the former is cupping (hijama) and reducing food intake, while the treatment for the latter is through the Quran and remembrances (adhkar).