A wireless keyboard that didn't use Bluetooth wouldn't be vulnerable to this.
I didn't really try to figure it out, but I expect paired in the sense of paired, not connected. Sounds like ios toggles a setting for HID when you pair the magic keyboard an becomes vulnerable to this.
If it’s “paired” in the first sense, then merely using a non-Bluetooth keyboard is not sufficient, you also have to make sure to unpair any previously paired Bluetooth devices. It would therefore seem important to find out what precisely is the case.
I didn't really try to figure it out, but I expect paired in the sense of paired, not connected. Sounds like ios toggles a setting for HID when you pair the magic keyboard an becomes vulnerable to this.