I believe a normal magic 8-ball has raised letters so they press against the top and push all the colored liquid aside. So a normal d20 with recessed numbers probably doesn’t work as well.

When I saw this posted yesterday, I started down a rabbit hole of figuring out how to make a magic d20 like that, but I couldn’t find any stls or 3D models of a d20 with raised numbers, since that wouldn’t make any sense for 99.9% of uses.

I found this video of someone making their own custom magic 8-ball with links to stl files with raised letters. Someone who knows how to create the files for a 3D printer could probably easily extrude the numbers on the faces, but that person isn’t me

https://youtu.be/u4psP7bPHW8