If Jesus was God, he knew he would rise and was never in real danger. Doesn’t “tested in every way we are” ring hollow when the outcome was guaranteed?

The Gospels do not portray a serene Jesus. Gethsemane has him sweating and asking for the cup to pass, and the cross has him crying out that God has abandoned him. The Christian claim is that the incarnate Son experienced fear, pain, and abandonment from the inside as a human being, whatever the divine nature knew; that is what the doctrine of two natures is for. The objection is really an objection to the incarnation itself, which the Trinity case takes up. Here the point is simply that Hebrews presents God as having lived human weakness, not observed it.