It depends on a lot of things, but the science is simple and universal. Most of the variables are in the rider, not the bike.

When i say my bike is good for 100 miles, that's constant assistance. I don't see the point in throwing in periods of non-assistance. If i have no assistance half the time, then that becomes 200 miles.

You can calculate your bike's ability with a few specs.

30ah battery - this means 30 amps for an hour.

On my bike, 30a is good for 1,500 watts. That's one hour of cycling at 1,500 watts (steady 40mph). So 40 miles.

Divide that into 5x 300 watt segments, that gives me five hours at 300 watts. Which is good for 20mph. So 100 miles, at 300 watts of assistance.

In my experience on the bike, this all reflects pretty well. Though my highest gear is 2kw at 45 amps, and the batteries can't reach 45 amps well within the hour. So the ampage release capabilities of the battery are to be considered when nearing heavy load.

Also, at 300 watts my legs are assisting a higher percentage of the overall output. Where as at 2kw the motor is doing almost all of the work.

Then there's battery cut-out margin. Not a lot of people know this, but when a lithium battery is flat/empty, it's actually not flat at all. Flattening it would kill it.
I've set mine to cut out at 45 volts. It starts off at 54 volts. If i set it to cut out at 40 volts, obviously this would increase my range. But it's not good for the battery, and would shorten it's life cycle.
Different batteries/systems have different tolerances and protections, so these will affect range also.

So stretching everything, i could claim ''Up to 500 miles'' perfectly legitimately. But it's meaningless. It makes the most sense to say ''30ah 54-45v @ 250w-2,000w'' and you can see what i have at my disposal from that.