There are several factors involved:

1. Speed - air resistance goes up with the square of your speed, no matter what type of propulsion system you have. So slower is always going to require less fuel than faster. The effect becomes much more obvious above 55-60 mph.

2. I heard from others and have seen on my Chevy Bolt EUV that you get slightly better range in city/varied driving than at constant high speeds. I think most of this is related to the exponential air resistance at higher speeds but there is obviously more regeneration, along with negligible air resistance, when in stop and go traffic. Once you get used to driving an EV in regen mode you will rarely use the brake pedal. I do use the extra regenerative braking paddle on the steering wheel if I'm approaching an intersection a bit too fast.

3. jack rabbit acceleration is inefficient in both gas and electric vehicles but less of a range/mileage factor in electrics vs gas.

4. A major factor in EV range is the outside temperature. This is due to batteries working better in warmer weather.  Both battery and gas vehicles lose "mileage" (mi/kwhr and mpg) due to heavy use of air conditioning. This time of year I get over 4 mi/kwhr and about 280 mi range where the EPA rating is 250 mi. In cold weather range goes down to about 200 mi due to battery temp and use of the cabin heater.