@TheMikke Unfortunately, RRF for the Duet 2 WiFi doesn't have the ability to talk to the TMC2209 drivers via the UART interface, and the Mini 2+ doesn't have an option to set the motor current using a potentiometer.
If you don't want to use a DueX5 (the DueX2 isn't produced any more), which is the easiest way to add 5 extra steppers, see here for external driver options: https://docs.duet3d.com/en/User_manual/Connecting_hardware/Motors_connecting_external
Ian