The keys can be printed with a filament change in Prusa slicer and afterwards running the added script. It changes the layer hight after the filament change so it is printed over the letters. In the FreeCAD file you can also edit the letters by yourself.

The Raspberry Pi zero 2 is solderd with wires to the display, there is a small amount of space in the case to store the wires. The goal was to have a case as flat as possible.