The manga added a lot of extra details as well as completely changed Momoshiki's transformed design. Most importantly the aftermath of the battle was completely changed to include new scenes introducing crucial plot points like Boruto's ability to see ghosts and the marking on his hand.
If they just skip ahead to the revised ending of the battle where Boruto encounters Momoshiki's ghost not only will people who haven't seen the movie be lost but people who have seen the movie but not read the manga version will be confused as to what changed and why.
My suggestion is they re-do the movie based on the manga adaption and use this as an opportunity to milk the Chunnin exams for filler, like showing the other students battles which will be more interesting now that we know more about them.
If they just skip ahead to the revised ending of the battle where Boruto encounters Momoshiki's ghost not only will people who haven't seen the movie be lost but people who have seen the movie but not read the manga version will be confused as to what changed and why.
My suggestion is they re-do the movie based on the manga adaption and use this as an opportunity to milk the Chunnin exams for filler, like showing the other students battles which will be more interesting now that we know more about them.
