Would it be possible to add the ability to right-click on the edge of a slide, or somewhere where there isn’t content, and have the ability to set the background for the slides and provide a simple file chooser so I can easily choose an image I have saved? I find the current way extremely confusing and non-intuitive.
You can do it like that today…
-
Right click on the edge of a slide, or somewhere there isn’t content
-
In the context meny click Slide > Set background picture for slide
-
Use the simple file chooser to selct an image you have saved.
(4. Select if you want that to be the background for the current slide, or all slides in your presentation).
Sorry if I am missing your question completely 
There is no “Slide” in the context menu (LibreOffice 6.0.3.2, Ubuntu 18.04). Is there a working solution to the original question?