Answering MadCap: You don't have to share Documents & Desktops to get iCloud sharing.  You can just move your company file from the Documents directory to your iCloudDrive directory (or any other directory that you are sharing via iCloud).   

As far as creating multiple files - if you are on Quickbooks Mac 2019 it should automatically synch the file that is in use.  I'm not sure how you got multiple files but hope you can figure it out - its likely the most recently modified one is the current one (also the largest - QuickBooks files tend to only get larger and never smaller).