One shouldn't have a throttle on a bike and that throttle is not going to help you as someone lacking athleticism, use some assist to help pedal and get some strength and endurance back. Also as we have said multiple times dragging a dog along is a bad move for so many reasons.

Typically when shifting I will ease up on my pedaling but for a derailleur I want to be pedaling while I shift but the derailleurs on department store bikes cannot handle much torque so go easy they are barely designed to work on a normal bike so adding an electric motor means more issues.