How do I accept I'm not the best? Pff, who says I'm not!?
Joking aside, the more time I spend in the industry, the more I discover that everything professional creators can do can be learned and/or copied. I can crack open "Drawn to Life" by Walt Stanchfield and read it and try to copy the techniques and learn to draw like a Disney artist. I can watch The Incredibles with the director commentary and learn how Brad Bird directs his scenes and viewer attention and tone so perfectly. I can read "Save the Cat!" and learn how to structure a story like a professional screenwriter. These abilities aren't magical gifts granted by spiritual beings, they're just skills people can learn. "angle your characters at a diagonal so they look more dynamic", "Write your story first, then go back and edit to make it all feel like it fits together".
A lot of the time, the thing that separates people who hit it big early in their career and people who take longer or who give up is really just privilege and luck. People are generally not born with incredible writing or drawing talent. They usually have some sort of mentor who taught them that, OR they copied it from somebody else who learned it. They usually also had some kind of support, like a mentor or advisor, a great editor or an amazing team.
Like, let's look at Star Wars for a minute. People always frame it like Star Wars just jumped from the mind of Lucas, super-genius man, wow! How can a person just make Star Wars!? ....Well... by learning, copying and.... having a great team. It makes sense, right? If he was a super genius man, how could the same guy who made the perfect movie that is the original Star Wars (A New Hope) also make... The Phantom Menace, which even though I personally can enjoy it, it's not....good.
An awful lot of the structure of Star Wars is heavily influenced by or straight up copied from Akira Kurosawa's The Hidden Fortress. The choice to set it from the droids' point of view (like the two bickering peasants from Hidden Fortress), the decision to make it start in media res, the decision to have tense sword fights... It was this mixed with a basic "Hero's Journey" narrative structure (which Lucas learned from a book) and the aesthetic of pulp 1950s sci fi as imagined by a great team of concept artists and prop and set makers. The space battles are copied from WW2 dogfight movies, to the point that originally they used clips from these to stand in for these scenes during production. Then of course, the whole movie when it was first made was SO BAD that Spielberg said it was awful (in much cruder language) and it was only made into something narratively coherent and watchable by Lucas' then wife editing it to within an inch of its life, and let's not forget Carrie Fisher's always underappreciated work as a script doctor making the dialogue better! (Rest in Peace, absolute heroine).
What I'm saying is, most of the time, genius isn't an island. Anyone can learn to be a great creator if they put in the effort and go through a learning process, or if they have an amazing team behind them.
Whenever I'm feeling down, I like to watch Hbomberguy's video about how RWBY fails to live up to its premise. RWBY was massively popular, but it's completely inept! It fails on so many of the rules of basic writing. Most of what's good about it either comes from Monty Oum (rest in peace) or is cribbed from other series (mostly Cowboy Beebop, Avatar and Korra). I watch that video and I think ".....I could do better than that!" I think that anyone who has put some effort into reading books and watching videos about narrative structure could write a better version of RWBY. Do I think I could write a better version of Avatar the Last Airbender? Hmm... maybe not? Or not yet? (I could probably write better than that episode where they're all in the canyon though. That one is mehhh) But I think I could write a better RWBY and that's a start, right?
The longer you keep studying and making things, the more things you'll see and think "okay, I think I know how this could be improved", and the more high quality those things will be. You have to start somewhere though. You have to take that step and make those mistakes that you'll learn from. So go and make them! Get your mistakes out the way now so that if you do get the opportunity of an audience and budget, you'll be a stronger creator who has learned from mistakes when that happens!