I designed my own for similar reasons, and it's interesting to see a somewhat similar position for the thumb keys. I optimised for hand/wrist position with minimal movement. However, I messed up the column stagger (off by one). Here's the writeup:
Interesting to see the thumb key positions are very similar to mine! Can you reach the outermost (outer regarding one half) thumb key without any issues?
Is your hand position like two columns for the middle finger instead of the pointer finger?
Yup, I can reach all three keys in each thumb cluster without a stretch. It's actually only a slight movement because my digits are quite long. My middle and ring fingers rest on the columns which are shifted up.
https://qubyte.codes/blog/why-did-i-create-a-keyboard