thinking what I'd want if i could like, design a completely custom keyboard (starting from a standard 100% keyboard)
For fun I tried to create your layout on Keyboard Layout Editor. Not sure I got it exactly right, but I tried my best (´·ω·`).
In regards to your comment about the Command key, Linux actually has a fourth modifier key called “Hyper”, though its mapped to act as another Super key by default, so—if I remember correctly—you have to mess with XModmap to change make it actually usable.

































