I have not yet dived into PCB design, so this is a hand-wire. The brains are a Raspberry Pi Pico microcontroller unit running a keyboard Python package called KMK. The switches under the keycaps are manually soldered in a matrix, with diodes to allow a human number of i/o signals but still prevent the RPi from accidentally detecting ghost keys.

Nothing new under the sun here, and I have learned a lot from the various resources out there, but there are not a ton of people doing their own keycap legends (this batch is underwhelming in color, but very serviceable), and most handwires tend to be ergonomic models that are more off the beaten path than this layout, which, TBH, is quirky but has a ton of keys and is pretty similar to several off the shelf models.