Was John the Baptist a Gnostic?
"1In those days came John the Baptist, preaching in the wilderness of Judaea, 2And saying, Repent ye: for the kingdom of heaven is at hand."
https://biblehub.com/kjv/matthew/3.htm
"Mandeans are an ancient religious group that first lived in southern Mesopotamia more than 2,000 years ago. Their rituals vaguely resemble Zoroastrian and Nestorian beliefs. However, their central prophet is John the Baptist"
https://i-cias.com/mandeans/
"20When the men were come unto him, they said, John Baptist hath sent us unto thee, saying, Art thou he that should come? or look we for another?"
https://biblehub.com/kjv/luke/7.htm
"The teaching of the savior, and the revelation of the mysteries and the things hidden in silence, things he taught his student John."
http://www.gnosis.org/naghamm/apocjn-meyer.html
"Mandeans of Southern Iraq. These peace-loving people are now fleeing to the west . They are the last Gnostics, the only surviving remnant of the ancient sects who taught the direct knowledge of God, created their own gospels and myths and were persecuted as heretical by the church in the second and third centuries."
http://www.andrewphillipsmith.com/john-the-baptist-the-secret-history-of-the-mandeans-2/
"The Mandeans are an ethno-religious minority population that originates in Iraq, Iran, and Syria. They were displaced from Iraq after 2003 as a result of extreme violence and persecution. Their Gnostic religion predates Christianity, Judaism, and Islam. Unable to defend themselves due to their pacifist religion, the 60-70,000 adherents were scattered throughout the world. There are about 2,500 Mandaeans in Worcester, MA.
The Mandeans are the last surviving Gnostic religion from Late Antiquity. In practice and beliefs, Mandaeanism differs from Islam, Christianity, and Judaism. They affiliate themselves to a chain of prophets starting from Adam the first man – as the first prophet- to John the Baptist (yahyā yohānā) – as the last Mandaic prophet."
https://mandaeansocietyma.org/about-the-mandaean-society-of-massachusetts/
"Gnostic religions view the material world as the product of a mistake in the heavenly realm, the creation of one or more inferior divine beings rather than the supreme God."
https://news.yahoo.com/tiny-minority-iraqis-follows-ancient-121827458.html
The Revelation (Apocalypse) of Adam
http://www.gnosis.org/naghamm/adam-barnstone.html