There’s a huge paradox with screenwriting, or really storytelling in any medium. You have to make stuff the same, but different. Your protagonist needs to be special, but also universally relatable. Your story needs to be fresh and original, but you also can’t really stray too far from audience expectations either or else you risk being “too out there” or “experimental, but it just didn’t work.”
Screenwriting is the art and science of doing the same, but different. The best movies have a good balance between the two. It might sound challenging, but I think it can be a huge help to think of things in these terms when trying to figure out your script.
When you’re writing your character ask yourself “what aspects of this character are going to be similar to my audience? What are going to be those pieces of themselves that almost every audience member can see in this character?” After you make that list, make another one. “What are going to be the things that make this character exceptional? Their sense of adventure? Their intelligence? Their stupidity?” Whatever it’s going to be, figure out what’s going to make a character different and then go out of your way to make sure no other character in your script has that trait.
You could also try a similar exercise with the challenge that your protagonist will face. How is this challenge similar to something everyone in your audience has faced before? Maybe it’s relatively obvious, something like a dating problem or not getting along with your boss. But in something a little more out there like a fantasy piece, that might be harder, but it will still be possible. After you’ve done that, figure out what twist you’re going to put on that challenge to make it interesting and entertaining in ways real life isn’t.
For example Harry Potter is similar to us in some ways (he lacks confidence) but not similar to us in other ways (he’s a wizard, he’s also braver than most people his age). The fact that Hogwarts is so similar to muggle schools means we can relate to challenges like trying to get good grades, make friends, etc. But then Harry also faces a lot of other larger-than-life challenges that no one else in his universe has, like being The Chosen One who can defeat Lord Voldemort.
You need moments where your character and their challenges are just like the audience. Without those moments, it’s hard for your audience to become emotionally invested in your story. But you also need moments that go above and beyond anything your audience has experience. That’s how you build interest on a more cerebral level, and how your script takes on the escapist qualities so many great ones have. You need both. You need the same, but different.