Interesting, I haven't had or seen any issue with 'z' not working before - 'E' should also work for interact (I also just realized that E is only shown in one of the scrolls and not reflected in the controls part of the menu)
Came to find out, it's the y button instead which works (alongside E, of course). it's probably cause I'm from europe and therefor use a qwertz keyboard instead of qwerty.
and the game somehow only recognizes the button at the bottom left there as the Z button
That's good to know - I'm using Unity's newer built-in input system which, I'm just reading now, is based on physical key location, as you mentioned. I'll definitely keep this in mind going forward. Thanks again!