Sonos Arc Ultra 9.1.4 or 5.1.2?

I recently watched a review comparison video on theRTINGS.com YouTube channel, which claimed that the Sonos Arc Ultra isn't a true 9.1.4 Atmos soundbar but rather a 5.1.2 system. I currently own the Sonos Arc with two Era 300s and dual subs (Gen 2 and Gen 3), and I was considering upgrading to the Arc Ultra specifically for the 9.1.4 Atmos upgrade. Can anyone clarify whether the Arc Ultra, despite possibly not being a true 9.1.4 soundbar, can still deliver the upgraded 9.1.4 Atmos soundstage when paired with my Era 300 surrounds?