If iReal Pro reports that iCloud Sync is disabled, confirm you are signed in to iCloud with iCloud Drive on, on every device, and that iCloud storage is not full.

 

As a last resort, Settings offer Delete iCloud Data, which clears the iCloud copy so it can be rebuilt. Back up first, then re-enable sync on the device whose library you want to keep.

 

For more, see Sync your library with iCloud on the iReal Pro website.