Adobe does not offer any more storage. You only get the storage quota which is allocated to your plan. That's it.
For the record,
Photography Plan only comes with 2GB Cloud storage.
Single App Photoshop comes with 20GB Cloud storage
The Photoshop Photography Program listed in that link is no longer available. It was superseded by the Creative Cloud Photography Plan.
I wonder if perhaps you misunderstand what that 20 GB of storage is for. It is not to store your master images. It is a way for you to create collections of images that you want to share on Lightroom Mobile to enable editing or sharing with others. Your master images still remain on your local hard drive.
Yes, you are right. Thank you for clearing it up for me.
Just came across this thread and don't know if this helps.....
If you upload originals through Adobe Photoshop Lightroom to the Cloud, then they will sync back to LR Desktop (in a From LR Mobile Folder)
Although this shouldn't be used as backup storage, it will give you access to your Hi Res images on Desktop, Web and Mobile (for many reasons traditionally you may not want to work this way, but I'll leave that to those who know more than me).
Unsure of the Data Limit, but I must have 30GB up there and have read various amounts, but the 20GB Creative Cloud Storage doesn't include photos uploaded from LR Mobile and Web.