There are a couple of options here:
- some sort of fanless (sealed) tablet running Windows — I run Carbide Motion on my Toshiba Encore 2 Write 10 — other possibilities include the RCA Cambio and Fusion 5 and Microsoft Surface tablets (just make sure not to get an Arm unit). Whatever you get needs to meet the system requirements for Carbide Motion
- getting a Raspberry Pi 4 and a touchscreen for it:
- getting an inexpensive Windows or Mac OS or Raspberry Pi computer and running it “headless” and connecting to it with a tablet and controlling using remote control software such as VNC — for a Mac it should work to use Sidecar on an iPad
- get a nice Windows tablet — I often run my machines from my Samsung Galaxy Book 3 Pro 360 (and before that my Galaxy Book 12)
That said, many folks just use the cheapest Windows laptop which they can find used.