Q1 Answer : I will be mostly on manicured road as we have here a trail called '' le petit train du north " that is 234km long. It is mostly flat with a few hill but nothing i can pedal up myself.
Q2 Answer : My guess is they go around 20km cruise speed but with lots of pedaling assistance. I might be big but i am still very athletic and my legs are my strong point... so i am not afraid to pedal and just use the battery and motor as a assist.
Excellent! A hub-drive like the Velotric Discover 2 (VD) will definitely work well for that.
I suspect that you'll need a 2nd battery to go 90 km at low but constant assist on that route with either the VD or the Himiway Zebra (HZ). But either might go 50 km on one battery.
If so, I'd recommend the VD. It will likely burn significantly fewer Wh/mile — especially at your weight, and that will at least partially offset the HZ's advantage in battery capacity.
The VD will also be
much easier to pedal with the motor off. Do enough of that on the flats, and you may well get 90 km from one battery.
Other reasons to prefer the VD (or a similar commuter) over the fat-tire HZ...
Weight: The VD weighs 16 lb less than the HZ, and the 2nd battery will probably weigh ~2 lb less for a total weight saving of ~18 lb when carrying a spare. That will increase your headroom for cargo on the VD, improve handling and agility, and reduce your total resistance (Tr), especially on hills.
Reduced Tr = lower battery consumption in Wh/mile. And better handling and agility make any bike more enjoyable.
Tires: The VD's 27.5 x 2.4" commuter tires will have a
much lower coefficient of rolling resistance than the fat knobby 26 x 4" tires on the HZ. That will further reduce Tr at all speeds and on all grades, with range increasing accordingly. The VD's tires will also improve handling.
This is why I recommend against any fat-tire bike for your purpose.
Drivetrain: The VD has an 8-speed drivetrain with a lower bottom gear. The HZ is a 7-speed with a much lower top gear.
Since you'll be pedaling to meet range goals, that makes the VD the better choice on hills, both up and down. And one more speed means a better chance of pedaling at a comfortable cadence.
Assist type: Already mentioned the VD's SensorSwap feature in my last post. After thinking more about it, may not be all that beneficial with your strong legs, and it WILL burn more battery in cadence-sensing mode. But it's a cool feature that you may find uses for when range isn't a concern.
I've given you a lot of educated guesses, but only testing will tell for sure. Good luck!