I mentioned it already in the general thread, but besides obvious suggestions like Duel of the Fates or Across the stars, I have a less-known prequel theme in mind, one that is prominent in the second half of ROTS. It’s a Sith motif named “Mystery of the Sith” also known as the second half of Padmé’s Ruminations. It has early hints to the “Anthem of Evil” theme if you listen it closely.
TROS really should serve as a culmination of the saga in all its aspects, including the score.
Is that really a motif though? I can only think of one time it’s used in the film.
I will say too the film as is already features a few quotes of prequel music.
It appears when Anakin is given instructions by Sidious, and also when Obi-Wan realizes he has turned to the dark side. I was suggesting to use snippets of it mainly because it’s less on-the-nose than other prequel tracks, and because of the similar notes to the Anthem of evil theme.
The film does reuse prequel music but it’s not that noticeable. I mostly remember “Yoda challenging Palpatine” track when Rey’s training on Ajan Kloss, and an AOTC track similar to the Kamino theme when Poe and Zorii talk on Kijimi. I’d have to rewatch the film to notice more similarities. For me, having Duel of the Fates during the final duel would be enough.