I am also using Rasberry Pi . I’m planning to use a full blown proper pc processor RISC V . I’m planning to use a laptop, mini fanless pc, or tablet to be the “brains” running the main software engine in the chest of the robot. This will then interface by USB with a series of Arduinos, Nervo board from inmoov.fr, molex sensor boards and servomotor controller boards. I am not using Pickaxe now, planning to use if needed for some specific modules in future.