Apple needs to at least adjust their iCloud storage tiers to match their phones. The jump from 200GB to 2TB is ridiculous and feels like extortion. The 50GB -> 200GB is also ridiculous because it can't even support a full backup of their base 64GB iPhone.
Your Backup does't include your all of your iOS and App Installation. So a 50GB in most cases should be able to backup a 64GB iPhone unless it is all Photos.