I have had a wild-caught African grey for 30 years now. The poor thing was terrified and had had several owners before i got her from a rescue place.. For 9 years I just talked to her, gave her toys and fed her. After about 3 years she started to take food from my hand through the bars but if I put my hand in her cage she threw herself to the ground and screamed. After 5 years I could stroke her head through the bars and started giving her food from my hand in the cage itself. Then she started rushing over to be petted in the cage. After 9 years she suddenly just stepped on my hand. I can do anything with her now and she will even let strangers pet her through the bars if she is in her cage. She has never bitten anyone, she just pushes them away with her beak if she doesn't want to be petted.
I don't know much about amazons but I think all animals respond to patience and kindness but it could be a very long game. Don't give up on the bird as they are often moved around from person to person and this just makes them even more insecure.
There are many good books and videos on how to train parrots too.
Good luck.