> it pays to have control and z close to each other

Well there you have it, control and z are not close to each other on my keyboard, yet control and a are.

What's your layout?

z near control is standard qwerty layout. you probably have qwertz which is actually less common globally.

but you are right, in your case z is not the right key. choose another. i use o as my main key now, not very close but close enough. alternatives i use and have used are q, s, d, x, and a few others. even ] can work if you have a US keyboard at least. i avoided a and e since they are used on the commandline often. (although elvish doesn't support them by default so that's training me to not need them there)