Find the moment, then rebuild the open
Scrub for a reaction, a clear tip, a disagreement, or a before-and-after. That clip is the body. The original long video’s intro is almost never the short’s intro. Write a new first line that states the point, then play the moment.
Reframe to vertical. Add captions. Change the title so it is not "part 4 livestream." One long video can feed several shorts if each one has its own promise. Ten weak crops of the same rant will not.