I built a cargo bike (box out front) and have fitted it with 48V 15AH battery with a 48V high torque rear hub motor. It sounds as if this one from Decathlon is almost identical in terms of power and capacity. It is hard to say what sort of autonomie you could expect as it would be very dependent on the load and how steep and how many hills you would have to deal with. One thing I can say is that there is very little need use the electric assist on the level or if there is the slightest downhill incline when loaded. The extra weight gives a lot of inertia. My typical trip is to the supermarket each week. The ride in is slightly uphill and I use the power on level 2 of 5 which allows me to put some effort in (which I like to do) and travel at an acceptable speed. For the return journey I don't even use the electric assist. Once up to speed the bike bowls along and on the couple of short inclines, where I would normally expect to put a bit of effort in on my solo bikes, the inertia of the loaded bike carries it up. The price of 2800 euros for a complete package is very competitive. However bear in mind that the kit that I bought for my cargo bike costs £659
https://wooshbikes.co.uk/cart/#/product/uid-251-dwg22c-48v15ahr/shengyi-dwg22c-48v-250w-rear-hub-kit-with-48v-15ah-rack-batterySo don't rule out converting an existing bike if it has the carrying capacity or if a trailer is an option.
BTW in the Youtube video the tester states that the gears use an 11-18 cassette, which didn't sound right, but checking on the Decathlon site it is in fact 11-28.
P.S. "autonomie" is French word
but I know what you meant as I lived in France for 21 years.
