I started using boric acid about 6-7 years ago. I’m nit talking about those ineffective foot powders, just straight pure boric acid (looks like powdered sugar), about a teaspoon every 2/3 days in my shoes.

Basically stopped all smells, no fungal infection of any kind for years, and at the end of the day, my socks still smell of fabric softener.

Doesn’t prevent sweat but the boric acid completely blocks the proliferation of bacteria, so no smells and no fungus can grow.

It’s more effective if you start using it on new shoes as they will never be contaminated by bacteria.

Truly amazing how effective it has been. Just give it a few weeks.