I am still very poorly after a long stint of anemia messing with my physiology, however it wasn't diagnosed till last minute and all systems were going down :(. I have hashimoto's disease, i take thyroid hormones. But even your ''own thyroid produced' hormones can 'pool' with iron deficiency, mine did and I became very hypothyroid but with hyperthyroid symptoms, one can have restless legs with just low serum iron, when not even low Hb. I developed many more things because of my overall untreated conditions, but you might not notice much more than the restless legs.
It may happen in too much iron I have no idea about that one.
So if you are interested in this hypothesis anyway, here is a good paper on iron dopamine and thyroid.
hugz and best of luck