How to swap Ctrl and Function key?

I'm trying to swap Ctrl and Fn on Catalina without downloading a new app. As suggested in multiple articles, I tried going to System Preferences > Keyboard > keyboard > Modifier Keys.. in hopes to simply swap the function of two keys. However, Fn is missing from the list of modifier keys. Am I missing something here? Do I need to do something else to make Fn key show up there?

EDIT: I'm using Macbook Pro with touch bar.

Solution 1:

From Apple documentation (Change the behaviour of the modifier keys on Mac)

On macOS 10.13 and later, you can also change the behaviour of the Function key on keyboards that have an Fn key – except keyboards with a Touch Bar.