Split Keyboard Firmware Assistance Required

Hi! I'm a hobbyist working on a split keyboard- however. I've run into a few issues with the firmware side of things. My keyboard is a ortholinear 6x3 split with a 4 button thumb fan running on a RP2040-Zero. I'm using a Japanese duplex matrix for the encoding, and as this is my first project building a keyboard from scratch, how much would it cost for you to walk me through some of the steps? I've attached my fork of the QMK repo so you can take a look at my progress ;) Looking forward to working with you, Baichuan Github: https://github.com/bo123-coder/qmk_firmware