Since we dont know what happened after Sasuke watched Jigen absorb the Juubi chakra and transform why not explore the possibility that Sasuke absorbed some of the ten tails chakra himself? Lets just say that the site with the rinnesharingan and the juubi is designed to create karma seals. I don't think that is much of a stretch since two of the four holograms represented at the site are known karma seal users (Jigen, Momoshiki). I don't want to get into how or why right now but if that were true Sasuke is definitely someone who would possess the ability to attain a seal. Why? He already has a rinnesharingan and the site appears to be set up to harness the power of the Juubi's rinnesharingan. He would already be ahead of the curve in that aspect. Secondly he has experience with curse marks. After observing Jigen absorb the Juubi chakra and say that he was coming for the kids with the karma seal he understood that the village, Naruto, and Boruto were in danger. So he made a quick decision to absorb the Juubi's chakra which caused him to leave an imprint at the site and create a newly formed karma seal. This caused his connection to Naruto to be heightened because 9 tails chakra is just a less dense form of Juubi chakra so he was able to sense Naruto even after he was sent to another dimension. This is what I think has happened off-panel to give them a fighting chance against Jigen and it sets up an interesting plot twist. So Naruto and Rikudo Sasuke engage in a long battle against Jigen in which neither side is gaining an advantage. Meanwhile, Koji confronts Boruto and Kawaki so that he may take them somewhere safer and figure out the secret to defeating Jigen. They go with him while Mitsuki and Sarada consult Orochimaru because Sarada wants to learn more about byakugo and Mitsuki wants to remove his limiter. Jigen realizes the situation has changed and returns to the earth dimension. Once he realizes that Koji and Kawaki are gone he returns to his headquarters to figure out how to deal with Naruto/Sasuke and track down Kawaki...