Use Function Keys as standard keys in specific apps only (No Touch Bar)

This question is for MacBooks without a touch bar. I would like to use the F-keys as standard keys, but only when I'm in a specific app (IDE).

When I'm not using the app, I'd like the brightness and other keys to remain without dealing with pressing Fn.

This is similar functionality to how the touch bar allows you to display F-keys in certain apps.