Just as an FYI, 2 months is barely any time at all when it comes to taming an untamed bird, especially one that was just rehomed 2 months ago from possibly a bad situation or maybe even a physically and psychologically abusive situation. I've seen birds that were still very young, under a year old, that were not hand-raised and we're scared to death of hands and people in general. And I'm talking about birds that were never, ever abused in any way and we're never rehomed. They were simply baby birds that were never tamed. And it has taken 6 months to a year or more to get them to the point where they would simply step-up onto there owner's finger inside their cage for 5 seconds...So you just simply cannot bring home an adult bird that has just been suddenly moved to a completely new environment with completely new people and who was very likely abused by his prior people, work with him for only 2 months, and then be like "I've been patient but it's been 2 months and I'm not getting any results".
You need to pick one method of hand-taming, whether it be putting a chair as close to his cage as you can right before he starts to flip out, then sit in the chair and talk to him/read to him for an hour at a time a couple of times a day, every day. Then each day see if you can move the chair closer, until you get right next to his cage and you are able to sit there talking to him and he's OK. But you must do this at his pace, not yours. If just this process takes 6 months then that's what it takes. Once you get there then you open his cage and sit right next to him with just the door open talking to him. Then once he's good with that you simply place your hand right inside his cage door and just leave it there without moving it for an hour while reading and talking to him. Then each day you try to move your hand a bit closer, but at his pace. When your hand gets close enough that he can easily reach without moving a millet spray sticking out of it towards him, then hold a millet spray I your hand without moving. Do this until he starts readily eating from the millet spray. Once he will eat from the millet spray without moving then you pull a bit of the millet spray back, requiring him to move a bit towards your hand to eat it. You do this until he has to step-up onto your hand to eat the millet spray, and you do this until he willingly steps up onto your hand to eat the millet. Then you try to move your hand towards the cage door, very slowly, each day until finally you are able to get him to step up onto your hand and you can take him outside of his cage on your hand. But all at his pace!
This entire process I just summed up might take a year or more, that's the way it is. Some birds progress quickly, some take months and months, some progress quickly and then regress again, and then some are so untrusting due to what they have experienced that it takes literally multiple years for them to trust anyone again. That's the way it is when you adopt an adult bird from a private party or a rescue. But when you finally do earn their trust you'll have it forever, and the time you spent every day trying to earn it was all well worth it. But you need to choose one single taming method, whatever it may be, and stick to it. Trying multiple different taming methods will generally not work, this process is all about consistency and repetition, doing the same thing with your bird every single day, as often as you can each day.
Where did you get your green cheek from? Do you know any history on him? How old he is? Have you taken him to your avian vet for his wellness exam yet?
And something else that may help you quite a bit since your green cheek is so scared that he flutters all around his cage every time you approach him:
Where do you have his cage located in your home? This is especially important in your situation, because of how scared and completely unsocialized with people your bird is. I'm guessing (I could be wrong) you have his cage off in a spare bedroom or in a room you're designating as "the bird room". Wherever you have him, I'm guessing that he is not in your main living room, TV room, den, or whatever you call the main room in your home that you and others spend most of their time. That is the room he needs to be located in, and if I were you I would move his cage into that room immediately. I truly believe that if you do this it will totally kick his taming into high gear. He needs to simply just be around as many people as possible as often as possible, even if the people in the room aren't directly interacting with him. Just having his cage located in the same room where you sit on the couch and watch TV, or sit on the computer, or read, etc. will help him so much. Having people in your home walk past his cage often will help him tremendously. Seeing you walk past his cage often, having you just say hello to him as you walk past each time, him being able to sit inside his cage and be able to see you sitting across the room on the couch will help him so much! This is socialization and he needs it. You'll find that after a few days of having his cage relocated to where people usually are, he will be a totally different bird. He will relax, he will stop being terrified of people approaching his cage and will no longer flutter around his cage violently, and he will relax enough around people and feel so much more secure and safe around people and their voices that he will really enjoy playing with his toys in his cage and entertaining himself while you're near him doing your own thing too (I hope he has a lot of different toys in his cage, he needs them).
"Dance like nobody's watching..."