Make it about one thing.
Because it takes time to write a script, first drafts tend to turn into lint traps for whatever is busy developing in the writer’s life.
Pro tip: This includes popular media. I have read scripts that morph recognizably into Jane Austen or True Detective or Broad City halfway through.
Be strict with yourself in your rewrites. Your story has one theme; it is about one hypothesis, building to one emotional tipping point. The build up should move clearly along a throughline that only proves that initial hypothesis, as opposed to proving many that turn up along the way.