Needless to say, and Graf goes into detail, the Gnostics and the Cult of Orpheus have striking parallels, and Irenaeus gives it way in his ranting.
It’s possible the Valentinians used a ‘pagan’ version of their mysteries for non-Christians (when they were hanging out with them).
Christians were beginning to move away from society in the 2nd century. The Valentinians offered an alternative for those who wanted to still be part of the Roman way of life.