I think I found an acceptable way to do this…
Opening: camera pans down to black. Then we just see hyperspace tunnel and the Falcon (shot from TFA trailer).

About the whole Palpatine… the first Resistance meeting is all about the fleet, not Palpatine. In the crawl there are infos about a rumored old Imperial fleet built by Sith Cultists (it’s way more believable to have the fleet being built during the times of the Empire, IMHO). No mention of Palpatine here.
Then, during First Order meeting, dialogue has been rearranged so that Kylo and the officials know about the fleet and that’s all. At the end, Kylo says: “My knights and I are going hunting for Exegol”. It sounds like a strange word: “Hunting”. But then we cut to Mustafar, so now the word makes more sense, considering that Kylo slaughters people.
Just after the encounter with Palpatine, I added the fortnite message. As background, I added a shot of Coruscant and another of Yavin IV, suggesting that this is heard all over the galaxy. And after that I placed here the short sequence where Rose, Poe and Charlie-From-Lost hear the message on the radio. This scene happens BEFORE the crew leaves for Pasaana.