Lightroom Mobile catalog feature

[#1]

Hello there, 

I am using lightroom mobile on a 2018 ipad pro as my main device and I am wondering how it is possible to move photos off of my ipad on to a hard drive but to keep the editing history much like a catalog on lightroom for desktop. I cant seem to find any answers to this anywhere. If anyone has any tips or ideas that would be awesome! If it isn't possible it would be awesome for this to be possible for the people only using a mobile for editing.

[#2]

The Catalog on mobile is held within the app and synced to the cloud.

It isn't possible to store photos on an external drive and still open and edit in Lightroom.