It’s not a good idea to reference the same files in both Elements and the Apple Photos App. This could corrupt your Photos library. You could export a copy or an unmodified original and bring that duplicate into Elements. You can also edit directly from your library in the Apple Photos app and save back into the library from the Elements editor app, but it requires an extension. See my blog link below for further information.
I purchased External Editor but it did not work for me using Catalina. After editing, when I tried to save it would only allow me to "save as" someplace else that was not Photos. Then I had to import the edited photo back into Photos. In other words the exact same problem that cause me to buy the extension in the first place.