The 21A is awfully complex & I bet you'll have a devil of a time finding a smith who has done anything other than polish bearing surfaces.
Oh, have you flung a .22LR across the room using the tip up barrel, yet?
Which reminds me, take extra care when clearing the 21A, as it has no extractor. Working the slide will NOT remove a cartridge from the chamber.
The 21A was my mouse gun of choice until I bought a Kel-Tec P32.
The P32 has a MUCH better DA trigger pull & recoil is negligible. My 21A has an ugly DA trigger pull, even after hundreds of rounds downrange. I was hesitant to dry fire it several thousand times, as I do most handguns, due to it being a rimfire.
I haven't shot the 21A in years...and I have since bought another P32 for my wife, who likes it a lot.
Good luck