Bebe, my little cockatiel was the same way, hated coming out of his cage, when he first came to my home. Bebe is rescue that came with a lot of baggage from his past. He is not cuddle bug, nor does he come sit with me either. We have worked thru some of the previous owners leftovers.
I have had him for 9 years, and he has improved a great deal. We started slow and easy, little things. Leaving his door open in his old cage with a treat at the door, something that he really loves, Nutriaberries. Only when I was home.
I will add DO NOT watch for a reaction. They seem to know that reaction good or bad is scary. let him work thru his fear, on his own. they do work thru it. after he has worked thru it, calm reactions; "such a good boy, you did all by yourself" that type of quiet praise. No big whoop or holler.
Bebe comes out only when he wants to, no force. He is terrified of hands,he will not step up for love or treats. Another huge terror is little kids, former abusers. So I keep kids back away from his cage. At a distance not so scary.
He has learned to "cage up" with my voice. That started as treat event also. He moved into a larger cage that he can walk on the top of, but getting him back for bedtime was trial. I started with leaving another favorite treat on door ledge, a sunflower seed. Gentle voice "cage up" showing him the treat, placing it at the bottom of the ledge. at first it was wait out game, "I don't have do anything you say, lady", but I can be as stubborn as he is. The scary part for him, I think, was leaning over the edge to grab a bar with his beak. Once he figured out that he wasn't going to fall, he went to the perch on his door. I grab the sunflower seed and reward him, closing his door. Now he does it without reward and it's a ritual.
Some birds are very independent. Humans are just there to feed them, clean their cages, to make their toys.