I can definitely help you with a bike rack to carry your e-bike with your 2020 Toyota Prius Prime but unfortunately there aren't any trunk mount bike racks compatible with the Prime model, and even if there were, most of them have a weight capacity of 35 lbs per bike - the most I've ever seen is 37.5 lbs per bike and it was a specialty trunk mount rack.
I recommend the EcoHitch # 306-X7369 and the Hollywood Racks Sport Rider SE Bike Rack for 2 Electric Bikes # HLY84FR which secures bikes... view full answer...