A Microsoft file hosting and synchronization service.
Gloria,
Has there been any further updates from your developers? As you can see when I first wrote this question it has greatly affected millions of people and businesses around the world.
Surely there is a fix, a work around or amendments that can be made to the current version of OneDrive for iOS that can have the same functionality as Apple Files app without having to use the Files app. Especially if it is security authetication issues between the apps, maybe a silly suggestion as I am no guru but why not cut out the root problem and develop and upgrade your own app to do exactly or better of what the problem app can do? No integration and working completely out of the one app. Problem solved then.