If you have in fact tried everything you can using positive reinforcement and it is definitely not working out, you can attempt to use negative reinforcement instead. You said that the target training/positive reinforcement methods are not working for you so I'm going to present an alternative. Basically it sounds like you are too laid back with the bird. Either you are scared of the bird or you just are too hands off. The fact that the bird sees you 7 hours a day is probably making it even worse.
The parrot is in a habit of "see" but "don't touch" with you. You've established this. You've established that you are safe to look at. However, the fact that in several months you have not handled the bird only reinforced its opinion that you are meant for looking but not touching. Now it's time to turn that around. Reach into the cage, corner the bird, and grab it from the back. Don't squeeze the belly cause that would cut off breathing. Squeeze from the top where the back and wings are just hard enough to keep it from being able to get out. It may try to bite you. If you can just take it, that's the easiest way. Just ignore the biting and wait for the bird to stop. If you are a bit scared you can use your other hand to hold its head or beak so that it cannot bite you. If you are really scared you can try wearing a think leather glove to do this.
Hold the bird until it stops biting. Even if it stops biting for just two seconds, release it and let it sit on your finger. If it will take treats from you then give some now. Wait a little bit and then grab it again. Once again wait until it calms down and release. Repeat this process. Eventually you should start to see some progress. The parrot will bite less, further apart, or after a longer duration if you are doing this right. Once you can get to a point where you can comfortably have the bird out of the cage, put it on a perch and attempt to follow my
target training method anyway.