My “radical” changes to the original trilogy would just be to blend more aspects of the prequels into it.
Prequel droids and vehicles. I would also retroactively add in the Ghost, from rebels, into the original 3 movies.
I’d have chopper seen in the background.
I would open ROTJ with a scene of Vader on Mustafar. Seeing him contemplate his life and on a black marble table lays things like Padme’s necklace, followed by a servant interrupting, letting him know the Emperors ship has arrived and is waiting for Vader to board. Then the next scene would be them on the death star. Then straight into the tatooine/jabba part of the movie.
I’d deepfake Hayden into the Vader costume at the end of ROTJ, and try and find someone to redub his voice to sound more like Hayden. I would keep the dialogue the same but add a line of dialogue that would hint that some day Palpatine may return, nothing too on the nose, just Vader letting Luke know that it’s ok to let go, but remember to persevere in the face of evil, which would then add to the Luke we got on the sequels in my opinion.
I would also regrade ROTJ so it looks better. It has a weird tint to it that makes it look older than ANH & ESB.
I would also trim alot of the ewok material, as the movie needs to feel more dramatic.