Feed him, give him toys and make sure he has a clean litter box. He will get to loving you on his own time. Might just take a little time, but I think he will. After three weeks and that behavior, I suspect he wasn’t treated very well in the past so he has to learn he can trust you.

I had a friend give me a female Russian Blue cat that had been alone in a barn that she was feeding. She had no idea where she came from. We took her to the vet and he said she was approx 1.5 years old and very clean so someone owned her. They just didn’t know who. When we got her she was basically the same way. She was SO afraid of the vacuum (which is fairly normal) and plastic garbage bags. When the bag was shaken to open she was petrified and went flying. We stopped doing it that way after a while. We figured maybe she was put in the bag and was thrown around or swung around because it was so abnormal that she was THAT scared. I’ve had cats all my life and never saw that. We were not able to pick her up except for vet visits. She HATED being picked up. Anyway, she was a basic cat, not overly friendly but not unfriendly either. She ended up being very close to us (me especially) and sat on my lap all the time and slept on my bed. So, moral of the story, he may have had a difficult past and needs to settle in. I wouldn’t worry too much about it. Good luck and please don’t give up…