From user JustTesting on https://www.elevenforum.com/
The copilot key on your keyboard isn't a single key input; it's actually a shortcut. When you press the copilot key, it signals the shortcut "Windows+Shift+F23."
When you utilize the Remap a Key feature, you can only remap a single key input at a time, so when you click select and then press the copilot key, it's as if you're inputting "windows," then "shift", then "F23." And since that feature only allows a single input, it saves the last one. This why when you press the copilot key there, it shows up as just "F23."
What you should actually be doing is using the Remap a Shortcut feature instead! This way, when you click select and press copilot, the feature can hold all 3 inputs associated with that button ("Windows+shift+F23"). Then in the To Send section, you click select and press your left control key. Click okay, and your copilot key should now function as a control key.
Make sure you delete any previous single-key remap you made for F23.