I call Rivian driver in the wrong here, right turn on red is supposed to be when clear after stopping. He did not stop unless well before the corner, then should have stopped at the corner once they could see oncoming traffic and waited especially since they could not negotiate the turn staying in the right lane.Rewatch the video and look at the corner the Rivian turned on, zoom in, might have your answer for the wide turn.
At least second video I've seen complaining about a Rivian driver avoiding an accident when the dashcammer didn't bother to review their own evidence prior to shame-dumping online.