I am using a Rpi4 with Stellarmate. It took a while to get it all dialed in but now it is a great setup. I use it with a Ultimate Power Box from Pegasus to provide power and a reliable powered USB hub. This is then all mounted on top of the scope. I run all the software on the Rpi, so Kstars runs on the Rpi and I just remote desktop into it. I have an outdoor WiFi access point so the Rpi is internet connected so I always have the right time and I can update easily.
As for focusing I have never got the autofocusing to work reliably. I have motor focusers on all my scopes and I focus in Ekos but I use a Bahtinov mask to achieve focus.