The GPIO on the PI is compromised for any hard realtime usage by the fact its running linux (ignoring what can be done with a lot of extra work with a RT kernel

The GPIO on the PI is compromised for any hard realtime usage by the fact its running linux (ignoring what can be done with a lot of extra work with a RT kernel and pinning cores). For non realtime use, the $10 USB->GPIO ones work fine on any computer with USB. In fact many of them are just ESP's, and work even better than the pi for hard real-time because you write custom bitbanging ardunio code and send the results/control signal over the USB. They become custom peripherals with a /dev/ttyUSB endpoint.