So far, what I'm hearing is that the word "Trinity" has no clear agreed upon definition. Therefore "God" (if "He" IS a Trinity - is NOT clearly understood as such). Folks who believe that God is a Trinity, do so because that is what they were taught, not because they clearly understand what that means.
"God" - in the Greek, means "divine being" - divine as opposed to human. "God" is not a name. "God" is a type of being, with personal characteristics - characteristics we associate with personhood. Sentient will (as opposed to instinct), communicative, responsive to the actions and emotions of His created beings (whether spirit beings or human beings). Pronouns like he, him, his, and who are used to refer to "God". "God" has powers beyond those of human beings. He is all-powerful, all-knowing, and everywhere present.
Yahweh, the "God" of Israel, IS the original and always existent divine being - one being, who beget a second divine being from Himself, before THEY created anything. The second being is also divine, and is therefore "God". Is this not what John wrote?