Honestly I think you’re better off spelling it out for the audience. It’s like, if I showed this to someone who wasn’t an Uber-fan, I’d want them to be able to tell me at the end of the movie, “Oh yeah, the throne had the power to keep the bad guy alive, so Rey destroyed it!” I might be wrong though!
Regarding the dyad, it has always bugged me that the dyad concept isn’t even mentioned until halfway through the movie, when Kylo calls them that. And what that means isn’t even explained until Palpatine starts draining their power at the end of the movie.
Right now, my idea is to set it up in the vision when Kylo touches Vader’s helmet. For a more normal approach, you could just add the line when Palpatine says it with some “dyad” imagery perhaps.
I have had this plan to use the Jedi whispers Rey hears on Ahch-To in the other movies. Like in TFA, when Rey is being drawn to the saber, and maybe subtly while Rey and Kylo are in each other’s heads during the interrogation. Finally, we’d hear the whispers when Rey is saying “be with me” at the end of the film, and they morph into the voices of the Jedi. On top of that, I wanted to include the voice of Anakin briefly whispering “Rey” when she being called to the lightsaber and the Jedi tree.
In this version I have planned, Kylo connects with Vader’s helmet again after meeting Palpatine to try and get some answers. Because at this point he knows Palpatine was using the helmet to manipulate him. But he wants to try and gain insight if he can, and he does, a little bit. This time, even though Palpatine’s influence is strong, Anakin gets through slightly.
Kylo: Show me.
Palpatine/Vader: Join me.
Ben: Grandfather.
Anakin: Palpatine lies!
Palpatine: I can give you…
Anakin: I brought you together.
Palpatine: everything…
Anakin: A dyad in the Force.
Palpatine: The Throne…
Anakin: Balance.
Palpatine: Power.
Shots of dark Rey and Kylo.
Anakin: No!!
I still want it to be stream of consciousness and vague, but basically, we see a Force battle in Kylo’s mind between Anakin and Palpatine. Anakin manages to get some info to Kylo, don’t trust Palpatine, him and Rey are a dyad. But Palpatine makes him misinterpret what Anakin is trying to say.
It doesn’t have to be Anakin, or he could say, “We brought you together” in a collective Force sense, but these things would be a way to show how Anakin’s influence has actually been countering Palpatine’s influence all this time. And, it actually shows where Kylo even heard the term “dyad in the Force”.