Another data point: (but no motors and no multi-core video pattern recognition)
My philosophy for Carl is to manage load to find limits and stay out of trouble. Perhaps, if you want to try really pounding a Pi4 get another one and put it on your desk. The GoPiGo3 board will not supply enough 5v to drive the Pi4 to the max, but will serve up enough for exploring lots of topics.
You can also just add a usb-c powerbank to the Pi4 power connector and use the existing batteries to power the GoPiGo3, no?