You shouldn't NEED your partner in a relationship. Co/dependency often isn't healthy. You should WANT them. And it sounds like she really wants you.
You are two separate, whole people, who chose each other to be your 'person'. Needing help/company etc from each other its fully expected, but its the want for each other that makes it all work.
Having 'the upper hand' in a relationship shouldn't be a thing, no one should have power over the other. It's not a competition to see who gets more attention from strangers or who is in a higher league. And wanting her to only be okay when she's with you is not fair on her and is an unhelpful thought for you.
Are you proud of her for her achievements? Her achievements don't make you a lesser person. She is doing what makes her happy, and I'm sure it would help both of you if you started thinking about how her achievements are positively effecting her, rather than how you think they negatively effect you - Her succeeding at something that makes her happy and she's worked hard for should only make you proud.
Her not getting jealous anymore is not a red flag, its a good sign, it means she trusts you. She trusts that you won't deceive her. This is a massively good and healthy thing, a sign that she wants you.
She brushes any advancements off, tells you she loves you, shows her love through giving you gifts, accepts and loves you for you. What else is it you want? Based on what you've written, you're feeling insecure about something that sounds extremely unlikely. You have only written good things about her and nothing that would make anyone think she's even considering anything but you.
Her confidence, growth and self earned success are things you should be mad proud of. Proud of her and proud to call her your girlfriend. You said it yourself man, she's the whole package. You've bagged a 10/10 who loves you - don't make it about you feeling inferior and wanting the 'upper hand' back, because that will be the thing that drives her away.
She clearly really wants you and really trusts you. I think it would help you to try and give some of that trust and respect back to her.