It sounds like you are doing everything you can.I can see how it'd look that way without context. The first time he nailed me, he was asking to be picked up to go inside. He got me when I tried to do so. He's been picked up to come inside since he was 3 days old, so I think he feels he HAS to come to me to come inside not that he wanted to be picked up. The second time he caught me by surprise because I wasn't trying to pick him up, but I was taking his food bowl (to refill it, the ungrateful wretch LOL). That one I think was bratty behavior, since I wasn't coming for HIM and he had to come towards me. So it is probably a combination of teen hormonal moron and legit fear mixing into a cocktail of dumb. It isn't helping that the adult hens are kicking the snot out of him during the day, which is making him very jumpy and unhappy in general, so he's not in the best of moods by evening.
As for picking him up, he will shake violently and dilates his eyes if you corner him with your hand near him (faces, feet, elbows do not get this reaction just hands). I suspect if I did it long enough he'd start panting and thrashing but I'm not interested in flooding him too hard. He will track your hands while tensing if it is near him. If given the option, he will choose to run away first, not attacking. I do think it started as bratty teen behavior with the sitter but he's definitely afraid of hands now. As I said, he spent at least a week of being roughly handled (not hurt but definitely handled too hard) - I asked the sitter to show me how he was picking the chicken up, which entailed jabbing at the chicken from different angles until he was too dizzy from defending himself then grabbing him hard with both hands from above like a hawk, staring him aggressively in the eye and swinging him a bit in the air during the trip to the crate.
I actually was doing what you suggested and it appeared to be desensitizing him a bit prior to the blood draw. Unfortunately, when he got my palm, I did react poorly/instinctively because I wasn't expecting it and definitely made it worse. I think he realized in that moment he'd made a very large error and exactly how much bigger I was, since I've never been anything but nice to him before. I plan to keep doing it (with gloves!) after giving him some space to get his head back on. He wants to be friends again, just not with my hands unfortunately
I did spend some time just see how far I could push him last night while he was in my lap. Not the nicest time, since he was trying to sleep, but it made him less likely to run all over the room in a panic or commit to biting hard. If the hand (singular) remains unmoving, he allows it next to him (but watches). If the hand is moving but is outside of a 2" range (probably his neck range LOL) he will alert, tense or train his beak on it. He particularly does not like hands near his shoulders and will peck if they come closer than the 2". If both hands came together, he'd get up to run. If you touch him physically, he will peck and he bites when you close your hands around him to pick him up. Just got to work on it more I guess, but I can see why people get upset when their formerly nice cockerel turns into a jerkbag
The shaking does sound like fear.
Do remember that why a cockerels becomes silly as they grow up is because of hormones; add fear and then you have a real bad mix.
Even if the fear part doesn't improve a great deal, as he gets older the hormones should settle down, which I do think will be a big help.
I bet when you were a teenager, you might have felt bad tempered one moment, and worried about something the next.