Let me try again.
The distance travelled when gliding does vary with respect to wind.
The best glide speed, which provides the maximum lift to drag ratio, does not change with respect to wind (air mass).
I get it, if there is a headwind equal to the best glide speed (which is NOT a normal occurrence) then you will make no distance whatsoever. And, if you push the nose over and gain some speed, you will gain some distance. However you will no longer be gliding at the best glide speed (maximum lift to drag ratio).
Let's put it in more realistic terms.
You have a 65 knot best glide speed (max lift to drag ratio).
You have a 15 knot headwind (far more reasonable than 65 knots at the level you're at where you need to seriously consider this)
Your airplane has a 1:6 glide ratio at best glide speed (about normal for most SEL aeroplanes).
You're at 3000 to 5000 feet AGL - again, reasonable for the exercise.
At this altitude, looking down at the ground, in a 45 degree "cone" angle, as I was taught. You will make any "field" (you can do the maths, I did).
But if you think that, due to the proof that at a 65 knot headwind, you will need to nose over to achieve 90 knots (or some other speed) in order to get to your "field", guess what, there are some areas within that 45 degree cone, that you will NOT make.
And, in most SEL aeroplanes, best glide speed is often full back trim, so you simply set full back trim, and then focus on trying to restart the engine, rather than trying to do the maths to figure out what speed you want to be doing to get the most forward distance (at a reduced time, by the way) and thus spend less time on trying to restart the engine.