I think you will get there.
I adopted a 9 yr old blue who would not sit on you. I got it wrong with his water bowl, providing too small a bowl, so he used to jump up and drink from the tap, getting a wet head in the process. Hence he learned to tolerate me holding him every day because he needed his head drying, which was followed by a kiss on the head and a brief cuddle with his legs hanging down, then I'd put him down carefully and run bith hands over the length of his body until I reached his tail, as he walked off, and I'd tweak his tail. Not too long, little cuddle, back safe on the ground.
I even remember the night he 'asked' to get on my lap!
By the time he died, he used to lay his ears if he didnt get hus chance to lick me properly when I was stroking him and he regularly slept on me, we napped on the sofa, he followed me everywhere, was carried about, we did shoulder dancing, everything. He was the baby I never had. I have a video of us before he died, dancing the the War on Drugs, then I sat down to fiddle with the video and hes just lying on his back in my arms looking around.
And all from a cat who was pretty hand shy, plus not an easily adaptable baby.
Keep going, I say! I'd try hand feeding one treat at a time and giving one stroke each time. Not too much, building trust and letting them experience the fact that you wont hurt them and touching feels nice.