I built a Planck, and as much as I appreciate the ortholinear layout, I'm having a hard time finding/configuring a keymap that has the necessary symbols somewhere that feels intuitive. I'll spend a couple hours acclimating to a keymap on typing.io, but if I need to an ANSI staggered KB, even for a couple hours, it seems to wipe my muscle memory. Guess I need to buy another Planck!
Keep practicing. I've used an ergodox for about 4 years with the Norman layout. I am still proficient at qwerty on laptop style keyboards.
Though I'm not a musician I assume it is similar to playing two different instruments.
This is why I went with an Atomic instead of the Planck. Ortholinear, but very close to a "normal" keyboard in the layout.
I use a special dialect of Dvorak, called Svorak A5 [1]. I think it is somewhat similar to what you describe. It is really liberating to have special characters on the home row.
I recently got a new mechanical keyboard, which had special "layers" for punctuation. "Common" punctuation like periods and commas are still there, but other punctuation like curly braces, brackets, etc. require new key combos. [1]
I agree with you that a lot of the time programming requires modifying rather than composing, but not all the time. In particular, I blog in Markdown, which requires a certain amount of extra symbols that I wouldn't normally be typing. (Goes hand in hand with the previous point).
[1] You might be wondering, "Why get a new keyboard, if you're typing slower with it?" The new one is easier on my hands, wrists, and fingers, as well as being an actual pleasure to use.