If you've never ridden an ebike, you don't realize how much power they generate. I can ride up moderate grades at 15-20 mph with modest effort on a 65 lbs ebike. Most lower cost ebikes are equipped with a 20 mph throttle. Probably half of ebikes have a top speed of 28 mph with a limiter and most could go up to 35 mph without.

Get on a Bosch equipped ebike and you will be very puzzled by the speeds you reach considering the level of effort you put in. Riding solo on flats requires a lot of effort to keep up with an ebike on throttle, basically impossible if they have a class 3 (28 mph). Don't even think about keeping up with an ebike uphill.