Germany (and the EU in general) has a very simple rule: bikes that can do only 25 kph even with motor support count as bicycles, no strings attached, and are free to use any bicycle infrastructure, ...
I'm a fan of pairing a torque sensor with a hub motor. It sort of enables the world's best-shifting derailleur gears because there is no stress on them, up or down. IMO when mentioning an e-bike is ...