There is a way actually to make fingers and wrists a little bit thicker.
i used to experiment with lateral synovial joint loading, it involves clamping the ends of bones (yes i am a weird phuk) and went to see if i can make my right wrist the same size as my left, as my whole left side of the body has a little bit thicker bones, left wrist is thicker, left foot is longer, even left thumb is longer.
So i proceeded with the routine and within a few weeks i noticed bone growth. It is kinda abnormal and it feels like a bump on the side of my wrist, but it definitely got thicker. And it is not some temporary swelling, it remains to this day, and at least 4 years had passed.
Also i generally had very thin wrists when i was a teen. They were friggin 6 inches in circumference. Now they are 7.5