If you loved Mobile Suit Gundam: The Origin III - Dawn of Rebellion, try Mobile Suit Gundam: The Origin VI – Rise of the Red Comet
A bridge between a film you've already seen and one most people haven't. Here's what they share, and what the second one does that the first one doesn't.

Mobile Suit Gundam: The Origin III - Dawn of Rebellion

Mobile Suit Gundam: The Origin VI – Rise of the Red Comet
What they share
Both films are directed by Takashi Imanishi, Yoshikazu Yasuhiko, and they both carry the epic, foreign gem, raw mood tags, and they sit in Action / Animation / Science Fiction territory. If that's the register that drew you to Mobile Suit Gundam: The Origin III - Dawn of Rebellion, the second film will land in a comparable space — through a different lens.
What Mobile Suit Gundam: The Origin VI – Rise of the Red Comet is
You witness the Battle of Loum, a turning point for Zeon. But their victory comes via mobile suits, and a pilot known as the Red Comet rises. Operation V begins as the Federation retaliates. Yasuhiko and Imanishi visualize a conflict where technology and charisma shift the balance of power, leaving a changed world order.