Homoousios isn’t in the Bible, many bishops signed under imperial pressure, and the dispute ran on for fifty years. Doesn’t that look like a political imposition rather than a defense of a settled belief?

The word is not biblical, the fifty years of continued argument are real, and the role of Constantine and later emperors should not be minimized. But the political story cuts against the invention thesis, not for it. If Nicaea had simply imposed a novelty by force, the argument would have ended. Instead the doctrine was contested, abandoned by emperors, defended by exiled bishops, and prevailed only when the Arian alternative proved unable to account for the church’s existing worship of Christ. A belief that survives losing political favor was not created by political favor.