For Palpatines broadcast, I think it would neat to use it to further contextualise the events of 7 and 8 as Palpatine arranging for his return, “at last the work of generations is complete, Skywalker is dead! The Republic Destroyed! The great error has been corrected, the day of victory is at hand, the day of revenge, the day of the Sith!”
Yea, that is the correct idea. If someone can extend this video (https://www.youtube.com/watch?v=Slsj4YeYaYQ) with “At last the work of generations is complete. The great error has been corrected. Skywalker is dead! The Republic is destroyed! The day of victory is at hand! The day of revenge! The day of the Sith!” similar to your suggestion, it will be perfect. I tried to exted it but I couldn’t mix the sounds very well.
That will make more sense Palpatine is just waiting to officially reveals himself to the galaxy after Luke’s death (Kylo was supposed to kill the Last Jedi, but…).