tefilin - Why are tefillin worn on the head and not between the eyes?

Take a look at these images of people wearing tefillin.

From this: https://www.karaiteinsights.com/article/mamzer

You shall tie them as a sign on your arm and as frontlets between your eyes.”

and this: http://biblehub.com/deuteronomy/6-8.htm

have varying translations. Some mention forehead between the eyes. Some don't.

Which one is right?

Last time I checked, our forehead is not exactly between our eyes. Putting tefillin between the eyes would require a diagonal string to keep it in place. Or using glue I suppose.

But that's not how it's worn. Why?