You have to unlink it from the library in order to make changes.
If you copy a navigation bar, then it will be passed as a reference. IF you make changes to the copied version of the navigation bar, then it will reflect in the original displayed navigation bar.
If you don’t want to have “Symbols” references being passed.
Now when you make changes it won’t reflect in its reference copies.
Glyphs are better than pdfs for iOS.
Hotkeys
r
creates a rectanglea
opens the artboardo
opens an oval