Assigning a Driver to a Device via API

It again depends.

i added these to traccar.xml because i'll not make the driver change from the device and i'll have multiple drivers on the same device

<entry key='processing.copyAttributes.enable'>true</entry>
<entry key='processing.copyAttributes'>driverUniqueId</entry>

which endpoint should i use to report the driver change?

The same one the official app is using.