Your screenplay is weak in those places where it intersects with what you don’t really know about yourself.
Not that you’re a great tangled mystery, but you take most of your own personality for granted and don’t notice it until someone yells at you about it.
Politics and religion and -isms are great examples of this, on an exaggerated scale. You know where you stand and where they stand and that’s conflict.
The blind spots happen on the small scale. Like, do you prefer to follow rules? Be punctual? Donate time and money? Do your share of laundry? Tell white lies? Be considerate of your friends? Are you always the smartest person in the room? Pee with the door open? Are you pretty sure that all happens under everyone’s radar just like it happens under yours?
Rest assured that someone else can’t imagine how you could possibly tolerate yourself.
That is character.
Too many spec scripts have protagonists that take it for granted that they are good and right and completely tolerable.
Get your protagonist out of yourself. Practice by picking one who thinks you are annoying or who annoys you. Put that protag out there, away from you, so you can see all of them.
You will be astonished how fast that protag gets into trouble, stays in trouble and has to change.