Shoe advice

I’m having a real hard time finding trainers that are suitable for my rubbish weakening legs. I’m sure some of you will relate to this problem. My weak legs mean I put my heel down first weakly and the sole sort of flaps down when I walk forward. This is now having the effect as my muscles weaken further I am falling backwards, especially in wet weather. I hate going out now at all and avoid wet floors, rain, leaves, snow and ice because of this. I recently had a fall in a cafe tiled floor as it was just mopped. I used to buy shoes from a company called Teva who made shoes for skateboarders and wet weather, they were great and although they still make some styles they’re expensive and they’ve changed the manufacture of the soles. I’m running out of research to find shoes with really good grip (rubber) at the heel. Does anyone know if there’s a liquid rubber I can paint on that sets on the bottom heels of trainers? Sooner or later I’m going to break a finger, hip or wrist and I’m not getting any younger Has anyone got any suggestions?