Your robot must have an operational Raspberry Pi at its core which carries out the majority of the computing effort.
If you feel that you can complete the challenge(s) using the Raspberry Pi Pico (or even multiple Picos) as the core, this is permitted.
Microcontrollers, such as Arduinos, micro:bits etc may be used on the robot but the Raspberry Pi must be in overall control.
Additional pieces of equipment e.g. a games controller, a laptop, mobile phone or tablet may be used to control the robot, but must not be physically attached when competing on the courses.
If a laptop can be used to “control the robot” (rule 4), but the Raspberry Pi must be carrying out “the majority of the computing effort” (rule 1), I wonder if a ROS-based robot would count or not. I’m thinking “not”.
But an out of the box based GPG3 could probably compete well.
/K