Psychological trinity model
Aquinas thinks that the Father, the Son and the Holy Spirit, while referred to as 'persons,' are not in any way like separate individuals . He thinks the essential distinction that makes up the Trinity is one of relationships that occur within God.
God the Father represents God. Proceeding from God is God's concept of himself, or his self-knowledge (what Aquinas thinks of as God's Son, jesus). And the Holy Spirit is the relationship of love between God's self-knowledge and God.
Remember the psycological trinity is also offical trinity.
But in this trinity version God did not create Jesus or the holy spirit. They was made when God thought about himself. So Jesus is God's thought about himself and Holy spirit is the love between God and God's thought about himself (Jesus).
Source:
Aquinas Blog - the Trinity
I think this version of the trinity make good sense
And no it is not modalism because the psychological trinity belief is that both God, God's self-knowledge (Jesus) and God's love between them (holy spirit) has their own form of self-conciousness.
I think this version of trinity is very much alike what Eddi wrote above: t's a
single entitiy made up of three
separate parts. Just like a triangle is a single entity made out of three separate lines...
It is almost impossible to say this is polyteism