That's pretty much what I did with Gergo[1], I got tired of the ergonomics of other boards and designed/built my own split board. It's smaller to reduce finger travel/extension, the layout is optimized for programming/vim and even tacked on a trackball. After too many terrible keyboards I made Gergo, and it is extremely comfortable to use for hours at a time!

There's some photos on my blog with the development PCBs (just got the production ready ones in and am shipping them out). Cases are in the works :)

I'm actually planning on adding additional modules (there's I2C contacts on every switch). And the trackpoint is next on my list.

[1] https://www.gboards.ca/

[2] https://pasteboard.co/HUI3Zqy.jpg

[3] https://blog.gboards.ca/2018/12/photodump.html

Sounds like you want this: https://ultimatehackingkeyboard.com/

(I want it, too, but it's kinda pricey)

I miss when laptops had trackballs. It was the only time in history when I preferred the pointing device on laptops to a standard mouse! (back in the 90s I used to use trackballs on my desktops)

I have not used this thing, and it's ugly as sin but this might do you: https://ultimatehackingkeyboard.com/ it has trackpoint and trackball modules.