A follow-me robot is not just a rover that drives toward a signal. The hard part is not hitting ankles, pets or furniture when the tracking signal jumps. The robot needs a desired following distance, low acceleration and an obstacle layer in front of the motors.
UWB anchors give much better distance estimates than Bluetooth RSSI. BLE can work for rough presence, but it is noisy indoors. Start with a walking-speed cart that stops confidently before adding speed or payload.