First make sure the saddle to pedal height is correct and then the tilt and then the forward back adjustment. If the fit is wrong a saddle won't fix it, you will still get a sore bum. If the fit is correct then you can fine tune with a different saddle. I tried a bunch of (expensive) saddles with my road bike before I finally visited a physical therapist for a bike fit. Visit a bike shop when you can and get a fit adjustment. It is worth the cost before you start throwing saddles at the issue. People are more likely just to throw themselves on an e-bike without fine tuning the fit adjustment because the motor can hide for a while some of the inefficiencies that will cause discomfort.