I did have athletes foot between almost every toe on both feet and nothing helped. I tried the common over the counter creams from the chemist but they did nothing.
Then I tried lugols iodine in a small finger pump spray bottle. Washed my feet and sprayed between my toes once per day and let it dry before putting on clean socks. It cleared it pretty quickly in about a week and has not returned in the last year.
I did use lugols 3% as that is all that I had at the time. It stains and you do need to be careful that it does not go anywhere it shouldn't such as carpet etc. I have since got some potassium iodide crystals which is clear and so would not stain. I do not know whether it would work as well but it might be worth a try before resorting to lugols.