Well first and foremost, you need to get rid of the idea that having confidence in your work means you're arrogant and cocky.
Frankly -- GET. RID. OF. THAT. NOTION.
This is one of the KEY reasons, if not THE very reason, you don't have confidence in your art. You keep associating "confident in my work" to "I think I'm better than everyone". That's not at ALL how that works. Having confidence in your work does not automatically make you an arrogant jerk who thinks they're better than everyone.
I dunno who taught you that or where you got that idea from, but you're gonna leave that at the door while you're here trying to improve.
Just -- -takes that idea of yours and throws it out of the window- -- Get rid of it.
When you are GOOD at something, you have to KNOW you're good at it. Because if you yourself don't have confidence in your abilities, you will not know how to improve. If you don't know your strengths, you're never gonna know your weaknesses, lemme tell you straight up. You'll spend more time trying to figure out what you're "bad" in than trying to improve the parts you should improve.
Even more, people will doubt your credibility. An engineer cannot doubt her abilities to be an engineer. A heart surgeon cannot doubt his ability to be a heart surgeon. An artist cannot doubt their abilities to be an artist. The moment you continue to do that, as opposed to saying "hey, I can improve", the moment more and more people will agree that "yeah, you're nothing at all"
Honestly? Time and Time again, this discussion comes up, and time and time again, it's your mindset that's holding you back.
When people give you supportive, strong criticism -- one that shows what you've done well and what you can improve one -- do not have your first reaction be "ok, you'e trying to fluff me up" or "stop lying to me"
Actually. LISTEN. to the advice
Ask questions, ask them why they believe so, have them point out where they saw the good and where they think you need to improve. Don't dismiss feedback just because someone objectively saw something good in your work.
Because that's not humble. It's demotivating and only furthers you away from progress.
Stop. Look, and Listen to the feedback you get that provides you ideas of what you've done well in.
Actually give yourself a break and stop thinking everything and anything you make is trash.
Just -- ERRRR, some of ya'll who do this kill me because you have amazing work and you're improving. I know it was probably force down your brain that confidence = arrogance, but that's not true at all. If you're good at what you do, you're entitled to be cocky every now and then. Just be good at bringing it back, being humble, and help others. When you do that, you're never an arrogant jerk.