The “official answer” is here: How to disable taxi ribbon and visual navigation aids in Career Mode
It’s says to do exactly what you’re doing. But a quick search of “blue boxes” will find several threads where folks want the ability to turn them off/on separately. So we’ll see if enough comments/votes can push the devs to change the current “feature” to give us options to do them separately, particularly in free flight.
I don’t recall seeing anything in the patch release notes saying it had been changed.
Regards