You’ll build a good relationship with him - it sounds like he wants to be with you, but doesn’t understand bite pressure

It sounds like he’s getting the recommended 12 hours of sleep, so that’s probably not a contributing factor.
He does get 12 hours and we did notice that if he has a diturbed night he seem ratty the next day. Unfortunately my partner is often up in the night through pain. I agree that he is not (or was not) too aware of bite pressure though lately I think he knows what he is up to.
This allowed me to turn my back and ignore them for a minute or two when they took off, taking the fun out of it for them. They usually parked somewhere pretty quickly, and then I would ask again for the step up and move back toward the cage.
- I found a wide range of tempting things to offer as I was putting them into the cage A few small bits of apple, a chopped up grape, a couple of raw sunflower seeds, pomegranate seeds, a nutriberry, a foraging toy with chopped up fruit in it, a bird kabob (shredding toy), etc. I made a big deal and happy noises, lots of praise everytime they went into the cage - and then hung out for a minute or two after putting them in to talk to them and check out what they were devouring.
He has gotten wise to temptations though he is an avid eater. One thing he might do from time to time is get a drink but he has to be fairly thirsty. When he is eventually in the cage he always goes immediately for a drink........thirsty work being out!!! A treat I tried with my pigeon in training though has gone down well with him and it is safflower seed. It is fairly hard to obtain. When I try pet shops etc. they seem to insist I mean sunflower.....Grrrrrr. I have trained him to fly to hand and such using it but again he is wise to it at "in" time.
As for toys it is not effective but he always gets curious when I am doing something with my hands such as preparing a toy or even working on other jobs. It is a nuisance at times as he likes to mess with my partner's PC mouse and such. So when I have been putting something new in the cage he has to be nosey and be there. It is something I might pursue thanks.
- When transporting to the cage on my finger, I sometimes would put my other hand just above their back (not touching them) and talk to them in front of me. The talking seemed to distract from the desire to engage in a fun game of “chase the bird”. The hand gave me a warning when the wings came up and I could attempt to divert their attention back to me. I never closed my hands around them to “catch them”. This worked well with Tango, he seemed to find comfort in having my hands close by. Baby hated having a hand behind her, so I dropped that tactic with her.
This approach has had varied results. Generally it is unsuccessful. My partner seems able to do this better than I but he tends lately again to know what it is leading up to and so lightly holding him as restraint is the only way that works. With several other birds I could grip the feet and they were happy with that. I tried this with this one at first gently holding but he struggles to get off and/or bites. He seems to not like any restraints (even before these get in troubles).
- I was attempting to show them that being in the cage was fun, and didn’t always result in a closed door that leaves them behind.
I tried this and for a few days it worked in that he came and went. I had made a platform for him to use which helped and I would get him to step up to it with a safflower seed. He would only go on it for a reward though. Normally I reward with a safflower and say good boy so that eventually I can drop the treat. I never closed the door when doing this as I wanted him to feel he was not being shut in.
A few things that I tried for biting: Tango was not allowed on my head or shoulders for many months - he was just too unpredictable with biting and left a lot of marks on me.
I may have made a rod for my own back over this. I always had my pigeon come with me on my shoulder (he was unable to fly at all thanks to injuries caused by a hawk). Normally I don't like having a parrot there but Daisy (the pigeon) had no bite to speak of and anyway never bit but groomed me. Letting this one on my shoulder was against my principles but being hand reared I let down my guard. I admit I trained baby (the name we use for GCC) to come to my shoulder. If I change rooms he (used to) fly to my shoulder or mostly head if I didn't take him on hand. In fact he flies around the house looking for me if I go off. Facing away therefore is no simple task and getting him off is now a problem. The T stick is an idea I'll try thanks. Trouble is (until recently) the hand is where he goes and then lately it is bite time
My fingers got so raw that I resorted to using flesh-coloured vet wrap around them to cushion the blows, so I could remove him and set him off me for a minute and ignore him when he bit (stopped me from yelping). I used a small t-perch (from his weigh scale) to get him to step up when he was in a particularly “bitey” mood. Saved me many bites! Particularly useful when stepping up in the cage (or I would just let him come out on his own if he chose to be unpleasant). Every bite resulted in a brief “ignore” or “time out” from me. It’s harder when they are flighted.....but possible.
I need to see about getting the vet wrap but have no idea where to get it or what to get. If i could show him that his bites are not affecting me we would do so much better I feel. His bites are not only fingers; he can gather my skin on my hand and crush it, my ears are favourite but the chin was the last straw for me. I see you mention flighted. I am convinced that wing clipping is the next big approach in this situation. In all my birds I have never wanted to do that..........I simply don't like doing it though I have just a few times. My last conure that I had back in the 1990s was a dream and no trouble apart from being very vocal if I was not with him.