I'm using a mini-PC with a 2-core Gemini Lake processor, 8GB of RAM, and 128GB SSD. It's $249 new now, I got it for $179 on a black Friday sale.
It's overkill for imaging-control. Plenty of speed and processor oomph and RAM. I run NINA, PHD2, ASTAP for plate-solving, Cartes du Ciel, and all the associated drivers (and iOptron Commander) for a CEM60 mount, 183mm-pro camera (20MB images), 2 EAFs, 290mm-mini guide cam, and 8-position EFW. A big plus is that it runs off of 12V (and is pretty power efficient), so everything I run is 12V and I can use a single 12V 30A power supply. Image downloads from the camera are 1-3 seconds, plate solves are 1-5 seconds. It's plenty fast.
WiFi on it is very good, but I ran a CAT6 cable from the house to the observatory just so the connection never drops. I usually control with Chrome Remote Desktop from inside the house, but I can also use Windows RDP. It came with Win10 Pro (a real licensed version). I started out saving files to a USB3 thumb drive, but got tired of walking out to the observatory in the morning to pull the thumb drive, so now I just save files to the SSD and copy them over the network in the morning.
You really don't need a super-speedy PC for imaging control -- you do for processing, but not control/acquisition.
My mini in my observatory control box below.