A default setting for the Apple Vision Pro using an external keyboard was driving me mad; the space bar and the tab key were hijacked to serve as Accessibility functions, which meant that in may places where you wanted to type, hitting the space bar would perform the “Activate” function rather than acting as a space bar. This was especially noticeable in iPad apps, but also happened in some native apps like Safari.
To make your keyboard act like an actual keyboard instead of a semi-but-not-really-controller, go into Settings –> Accessibility –> Keyboards and turn OFF Full Keyboard Access.