Oh, actually, another thing I’ll mention. If you want to 3d print something but don’t want to shell out for a 3d printer, there may be some options:

• You might check with your local library to see if they offer 3d printing services. (My local library has a 3d printer that they allow anybody with a library card to use for a very reasonable per-minute-of-printing-time fee. A keycap or three would take a very short time to print.)
• You could also check to see if there’s a hackerspace in your area that allows the general public to use any 3d printers they have.
• I could swear Thingiverse had a feature whereby users could mark themselves as willing to do custom 3d printing for whoever might want to contact them.
• Etsy has some shops that do custom 3d printing like this one.

I’d imagine there are probably other cheap resources as well. The only danger here is that you might get hooked on 3d printing and have to get yourself a 3d printer.

Also, just from a little searching, I ran across this free 3d model of a Keychron keycap that might be almost exactly what you need.

Finally, there’s a chance that if you print something with higher resolution, you might get a slightly looser fit. So if you end up getting anything printed on a resin printer, you might need to take that into account.

Whatever the case, good luck!