Bicycle to tricycle conversion kits
It might be more practical to invest in a trike that is a trike by design through and through. I am not sure what your budget is like, but this sounds like what you need. It's still a Pedal powered tricycle, but the electric assist will help you up that hill, especially if you are loaded down with groceries, etc. https://www.vitalitymedical.com/ewheels-ew-29-electric-trike-red-bundle.html