the world of forms is analogous to the monad, the world of matter to the dyad. the monad is the oneness, the fullness, which experiences itself through an externality, which is the dyad. Sophia and the demiurge are the dyad, Sophia is what falls away/emanates from the true God and the pleroma (the monad), Christ is what brings the fallen creation back to the monad/the return
The Valentinians definitely were heavily influenced by Greek thoughts, especially Platonism and Pythagoreanism. But your idea of Forms=Monad=Pleroma, Matter=Dyad=Sophia is plainly mistaken.
First of all the Valentinian texts found in Nag Hammadi show a slightly different theology compared to Irenaeus' Great Account.
But let's start with Irenaeus' account:
According to him, the Valentinians believed the first principles were Ineffable (male) and Silence (female). This pair produced Parent (male) and Truth (female). They then produced four more paired aeons which formed the Ogdoad. The Ogdaod are the paired aeons of Human, Church, Life, and Logos with the four aforementioned paired aeon. These four (human/church, life/word) produced 22 other paired aeons, and together the 30 are technically all in Pleroma (Fullness). But there is a limit placed between the Ineffable/Silence+Parent/Truth and the rest, as well as a limit between the rest of the rest and Achamoth (the Mother). It's one of the last in the set of pairs produced by Human Being/Church. This Mother is responsible of Christ and the demiurge, but Irenaeus does not call it Sophia. So no, in Irenaeus' account, the proper pleroma within the limits contains 30-4-4-1=21 aeons, it is not the Monad, and it is not even the highest "forms", which are in the Ineffable.\
From the horse's mouth:
He maintained that there is a certain Dyad (twofold being), who is inexpressible by any name, of whom one part should be called Arrhetus (unspeakable), and the other Sige (silence). But of this Dyad a second was produced, one part of whom he names Pater, and the other Aletheia. From this Tetrad, again, arose Logos and Zoe, Anthropos and Ecclesia. These constitute the primary Ogdoad. He next states that from Log os and Zoe ten powers were produced, as we have before mentioned. But from Anthropos and Ecclesia proceeded twelve, one of which separating from the rest, and falling from its original condition, produced the rest of the universe....Christ also was not produced from the Æons within the Pleroma, but was brought forth by the mother who had been excluded from it, in virtue of her remembrance of better things, but not without a kind of shadow.
Now for the Monad and Dyad you are talking about, I think it can most closely be related to the Valentinian text found in Nag Hammadi,
A Valentinian Exposition. Here it mentions Monad, which is the Father, and it is the Ineffable (male) that
dwells in Silence. It's a Monad because it is not paired, and there is no primary Dyad. Dyad means paired aeons, and the Father produced the Dyad and Tetrads. Sophia has her pair, which this text identify as Desire, and she gave birth without her pair's consent. So no, the demiurge is for sure not a dyad with Sophia.
No matter which account you take, the cosmology of Valentinians are much more complex than the og platonic Matter vs. Form. Matter is not even the issue here, because when the Son descends to fix Sophia's mistake he has to make her "form-less seeds" to be proper creation. He then ascends back into pleroma to form the "forms" in the Platonic sense which the lower creation is based on. The world of "forms" for our world is created by the Son to fix Sophia's mistakes, it is not analogous to the Monad, who is the Father that produced the Son. The issue with Sophia's bastard creation is not that is
has matter, but that it
only has substance but no form. Ancient medical theory believed the mother contributes to the substance of offspring, while the father contributes to the form. Sophia gave birth without Desire, and thus the creation has no proper form. That's where the Son comes in.
I understand your train of thought, but even if you take a simplistic view one has to view the Dyad as belonging to the realm of Platonic "forms."
Evil in either forms of Valentinianism I mentioned is not the result of it being part of the Monad, or the primary pair of Ineffable/Silence. Or any of the aeons they gave birth to. All that are in the Pleroma are good, and evil in this world are caused by Sophia being silly and not properly giving birth. I don't understand where the "Monad experiencing both the good and bad" can come in
They did believe realizing this world is shit is the key to salvation, but definitely not in the way you described. It's all shit because Sophia fucked up, not because God is both good and evil or whatever. Either version of Valentinianism believes Sophia's repentance and punishment are appropriate. Neither believes it's good to be bad.
