For hub motors, I would personally prefer 10S Dual Hub Motor 75KV on Dual VESC. I’d even use 90mm wheels which I should have soon in black.
Flat ground is awesome and you shouldn’t have any problems. Riding a hub motor setup without any belt drive resistance is pretty nice. If you plan on climbing lots of hills, you might run into heat issues for long rides 15+ or overloading the setup (haven’t tried it yet). If you climb hills, you want to go at a fast speed/pace to limit the heat you put through the motors but you’d be surprised at speed they climb some pretty steep hills.
They aren’t like a belt drive, there is not much torque on start-up and you can’t climb a hill with a 5 foot run way. You’d have to wait for the start-up (but once it’s going, you can get to 20mph easy). With hub motors, you might need a 10-15 feet run way and you can climb majority of steeper hills.
Benefits of Hub Motor is the riding style, it’s definitely a more free, coasting riding style. Brakes are nice and soft. Just riding a hub motor is pretty amazing and after start-up the get up on a hub motor is impressive. It’s shocking IMO how well they perform as well initially considering that they wouldn’t perform that well.