Einstein had something to say about relative motion and the point of view of the observer.
To this day everyone speaks of the sun rising in the morning as if it were moving and not the Earth.
So the language involved in Joshua reveals that they used language in the same way that we do. It says nothing more revealing about nature than our own daily use of language does.
So if you do not accept that part of the Bible as the literal truth then what other parts do you think are wrong as well?