Hey Chris,
I’m sorry for that.
I don’t know if you want to try again to find a touchscreen for Onefinity CNC Controller, it’s simply searching for a touchscreen that runs on a Raspberry Pi 3 under Raspberry Pi OS version 9.3 Stretch from 2017 with a Linux kernel 4.9 (as explained here). That’s because this is what’s inside the Onefinity CNC Controller.
However if you don’t want a touch screen, besides using the Onefinity Controller remotely from another computer via ssh, you can use any HDMI (or DVI-D or DVI-I) monitor, in conjunction with a mouse and a keyboard. The desire to use a touchscreen on a CNC milling machine comes from the fact that when milling wood, there could be wood dust around, and most keyboards and mice don’t really like that. However since ball screws are not compatible with wood dust (see example here) you would use a strong dust extraction system anyway, so maybe using keyboard and mice instead of a touchscreen would be okay.
Welcome to the forum.