First off no matter what point you are st now, with all 3, you can get to a better closer relationship.
When you brought the 2 GCC home, what did you do? How often did you hold then and take out if cage?, did they step up for you at the breeder?
Sometimes learning to read parrot body language is a skill that has to be developed. And nit everyone can be a " natural at interactions and training. For that reason , I'd encourage you to see if the breeder would let yiu observe him working with their birds. Likely not, most would not, but just incase they might it could be really helpful. Or find a behaviorist to come to your home and work with you. On YouTube Bird Tricks has many great training videos.
Shaping behavior or Shaping training or called ABC applied behavior. Works by slowly Shaping or train a behavior like step up.
I have some good all around links to share.
https://lafeber.com/pet-birds/stress...ot-companions/
https://blogpamelaclarkonline.com/20...ot-to-step-up/
http://freedomflightsparrotrescue.ca...rrot-behavior/