A simple CAN<->USB Transceiver with the help of STM32G474RET Nucleo board, Waveshare SN65HVD230 CAN Transceiver & Any FT232 UART<->USB Adapter. The default baudrate is 500kbit/s, it's hardcoded. I didn't need to change it yet.
Dekstop application for this firmware can be found here.
https://github.com/kurta999/CustomKeyboard
If you just want the desktop application, just buy Lawicel CAN USB.
https://www.canusb.com/products/canusb/
Everything
Nucleo
Waveshare CAN Transceiver
FT232
RS232