I'd like to be able to toggle the visibility of the coordinates with a key. This could either be a new "visibility" option "toggleable", or it could function in all visibility modes.

the fact that this existed before 1.21:

Sorry, I only just got back in to minecraft after a considerable gap. I don't know about any previous versions.

I would like this too, it would be the perfect replacement for a minimal F3 menu that can be toggled when needed