Terry edits 4K video with his iPhone 11 Pro Max. But when he makes changes, the upload to his iMac is very slow. Leo says that no online backup is going to use all the bandwidth you have to backup. And your upload speed is always drastically lower than your download speed. Leo says that Apple does offer iCloud backup on your mobile phone, but it's only 5GB for free, and the data isn't private. You can buy extra bandwidth, however. Leo recommends also backing up directly to your Mac.