to have the torque sensor inside the rear hub is not the best arrangement.
I have learned this lesson the hard way in my Woosh Sport TS. D8veh tested it a few years back and pointed out that when you climb a hill, the torque sensor hits the max pretty quickly.
A torque sensor in the hub is not necessarily a bad thing. The one Woosh used was a bit rudimentary. It had a separate plate on springs. The problem was the springs bottoming out and bouncing, which gave the feeling of a loose crank.
There's plenty of other ways to measure torque that wouldn't have that problem.
if you measure the torque from the cassette of inside the motor, your result changes with the selected gear.
measuring torque at the bottom bracket is my preferred arrangement.