So long as you have a reasonably plain colour background you can achieve an advanced layering technique. The thought came to mind watching the original video for Sophie/Bronwen/Kristian's change of track, Bullet For My Valentine's Throne, as illustrated in the screenshot below:
her 2017 video;
It was easy to find both official Apple and user guides for this with a clear search phrase, something you should bear in mind whenever you see any FX you think you'd like to use. FCPX has its limitations, but it is still a very powerful tool.
I've not yet looked into this in any great detail - you may find you need to research further. The key term is compositing - see this google for more: