I would just copy some tutorial for the your first custom keyboard and only add changes when you are confident with the basics. I watched a guy on YouTube building a custom keyboard and it was already quite a big project. It's very easy to underestimate projects and overestimate your abilities.
The only reason I would build a custom keyboard, is if I had strong material engineering knowledge (which I don't), had research on the biomechanics of my specific hand for computing the optimal geometry of the keyboard (which I don't), and had a good idea for the time investment required (which I also don't).
The Imprint keyboard does make keyboards taking photos from your hands as input. I have no affiliation with them.
So, objectively, building a keyboard should be seen as a hobby, a way to learn a bit about PCBs, microcontrollers, etc. Expecting a keyboard to be better, might be too optimistic.