The ROTJ parallel is definitely noticable in the finale, but with the ground combat split in two (human action scenes and the Gungan battle). That’s enough of a difference for me to write off an entirely intentional mirroring of the third acts.
That’s the whole point of what ring composition is. The mirroring and parallels must be different to work as visual poetry just like written prose or musical prose as Richard Wagner developed using the same techniques.
The Gungans and Ewoks are meant to parallel each other but be different.
Padme, Panaka, and the Naboo soliders taking back Theed Palace is meant to parallel Han, Leia, and the Rebel soldiers entering the shield generator bunker but be different.
The space battles and lightsaber fights are meant to echo Return of the Jedi but also A New Hope and Revenge of the Sith. This is “rings within rings”.
It’s about playing with different techniques and refreshing the idea to create something new to juxtaposition off of one another. Repeating isn’t poetry and tends to be what you find in the Sequel Trilogy.