If you loved Gundam Wing: The Endless Waltz, try Mobile Suit Gundam 0083: Afterglow of Zeon
A bridge between a film you've already seen and one most people haven't. Mobile Suit Gundam 0083: Afterglow of Zeon has roughly 3.0× fewer votes than Gundam Wing: The Endless Waltz — it's a deeper cut, not a mainstream recommendation. Here's what they share, and what the second one does that the first one doesn't.

Gundam Wing: The Endless Waltz

Mobile Suit Gundam 0083: Afterglow of Zeon
What they share
Theyboth carry the epic mood tag, and they sit in Animation / Science Fiction territory. If that's the register that drew you to Gundam Wing: The Endless Waltz, the second film will land in a comparable space — through a different lens.
What Mobile Suit Gundam 0083: Afterglow of Zeon is
You're a rookie pilot in the Earth Federation Space Force, assigned to test new Gundam prototypes. But a Zeon ace steals a nuclear-equipped Gundam, reigniting old conflicts. The clock ticks. Imanishi's direction lingers on the mechanical designs. It leaves one pondering the cyclical nature of war.