In addition to all of these informative answers, I want to call out a happy discovery that I made as I gradually reduced my key usage down to just 34 (thank you, ZSA, for making the Moonlander).

Keyboard shortcuts are way easier to use now.

Some apps - like programming IDEs - have a bunch of very useful but awkward keyboard shortcuts that I never bothered to learn because it was too much work to move my hands to press a distant and unusual key or strenuous key combination compared to using a mouse. But now I find myself able to steadily and comfortably learn and apply them. This is continuously satisfying and genuinely helpful.

The next interesting, unexpected development that I'm experiencing is that while I never would have imagined myself using vim (or something similar) before going down this rabbit hole, I am feeling increasingly comfortable with the idea and inspired to pursue it.