I couldn't find an Osu keypad using the Rasberry Pi Pico so I designed my own using mechanical switches
To build this you will need 2x Cherry Mx or equivalent switches, 2x 1N4007 diodes, 4x M3x12 screws, a Rasberry Pi Pico and some thin coated wire.
For the firmware, I recommend using KMK it is relatively simple to set up here is a link to their guide
For wiring, the keypad read through the QMK guide , in the end, it should look something like picture three but attached to the pins you chose in the firmware
For keycaps, I used some Keycaps off my keyboard or you could print these ones on Thingiverse
0.12 mm layer height
The author hasn't provided the model origin yet.