No Progress with Ringneck

Hello there, I purchased an Indian Ringneck around a month ago to keep personally after working with birds for years in a zoo setting and I've tried to use all the methods I've learned in work and research but I seem to be making zero progress with forming any sort of bond with the bird. In fact I feel like its getting worse.

Obviously she's new and I expected some apprehension but I'm literally in the room with her every day for several hours, I talk calmly to her, hang out near her cage, and offer food which unfortunately the only food item she shows any interest is apple, she adamantly refuses to eat anything but apple and her seed mix.

However in terms of fear she is still completely terrified of my hands and if they come near the cage she flees to the furthest perch and wants for me to pull back. She also freaks out anytime I open the cage door to clean or swap perching and enrichment. She will come to snag a piece of apple if I set it through the bars and remove my hand but she does so in a way I can tell is trying to sneakily get it. She waits for me to not look or inches closer to grab it and run away. And now even that has degraded, the past few days shes taken to just pacing back and forth on a perch if I sit near the cage.

If I'm not near the cage for awhile she does start to vocalize, several different sounds. Which I believe are social sounds based on videos if the species, but again if I come near the cage she becomes fearful and quiet.

I don't understand what I'm doing wrong here. I've never seen a parrot this afraid to the point she won't even take food from my hand.