If it is athlete's foot then this is a kind of fungus and the fungal spores will already be in your shoes and socks and will re-infect your feet again when worn. Socks get washed but what about your shoes???
I caught athlete's foot in the RAF and had sweaty, smelly feet for years until someone told me that only one thing would kill it, Boracic acid powder.
This powder cannot be bought now but you can get BORAX, a washing aid, which contains it.
Sprinkle this in your shoes to kill the spores.
I also found that by soaking my feet in hot water to which some borax is added ( 1 tablespoon) and leave soaking for 10 to 15 minutes then let dry naturally, the borax will penetrate the top layer of skin and kill the buried spores.
I last soaked my feet about 10 years ago and have not had any problems since.
Obviously, I would say that you do this at your own risk as I cannot be responsible if the effect is different for your own feet or problem.