My friend @RiirReeRii comes out with another argument against The Trinity

P1) God exists a se (From the definition of "God)
P2) The Father begetting the Son/Generation is a causal relation.
C1) Therefore, the Son exists ab alio.
P4) The Son is God (From, "Trinity")

C2) Therefore, the Son exists a se (From 1, 4)
C3) Therefore, the Son is exists both a se and ab alio (From C1 and C3)
C4) Therefore, "The Son" Is self-contradictory
C5) Therefore, The Trinity is self-contradictory

By a se we are just referring to God's aseity (i.e, the term a se means "through itself"). Aseity refers to God's uncaused, independant, unconditioned, necessary, etc. Existence.

We are simply exemplifying how God's existence is independant from and unaffected by anything outside of him. It's important to note that "Aseity" doesn't just mean "metaphysical necessity" / "existence in every possible world", since we could have Ab Alio necessities as well.

Ab Alio simply meaning, "Through another." In contrast with A se.

The second Premise might seem a bit weird. Someone might argue that the relation between the Father and the Son isn't "causal" in any sense. But this is just heretical.