I actually think Jar Jar is playing a great devil’s advocate role for this idea, because it does require a bit of work to figure this shit out.
That’s actually why I think having a more extended vision montage, in the vein of Dom’s edit of Kylo touching Vader’s helmet, would be beneficial to the moment she touches the blade. Rey blinks right as she says, “No”, in that shot where she holds the dagger. You could potentially slow her blink down, as if she were closing her eyes to focus, then go into the vision sequence. Get a few shots displaying Rey’s “darkness”, and she’s rewarded with a glimpse of the Death Star. Then Kylo interrupts her.
I think something like that could potentially show more intent regarding what Rey did to obtain that knowledge. So the audience isn’t left wondering, “If Rey just kept holding it in the cave, would it have eventually shown her the location of the Wayfinder?”
Two other things I suggested before, to help make it more apparent: coloring Rey’s eyes Sith yellow just before/after the vision; and also, in the vision montage itself, I think it would be neat if we could replicate the same kind of filter that was used in Episode III. Not only would it have significant Dark Side implications, but it would also help to differentiate it from the other visions Rey and Kylo have during the movie. Plus, I think it would be nice to have a little callback to the Prequels.
Here’s a thought: with the new Dark Side Knife idea, could that be the influence that pushes Rey to activate Force Lightning? Like, the Dagger is really starting to unlock her Dark Side potential more than ever before, which is why she couldn’t use it immediately? Maybe add a couple of Sith Whispers right before the lightning launches or something.