Sounds like you are using the wrong version of Lightroom. The Photography plan is basically Lightroom Classic and Photoshop. You do get Lightroom (desktop) and 20 GB too (and apparently that is what you are using right now), but that is more or less to test it out. Lightroom Classic does not need any cloud space at all. It stores the photos locally. If you want to use Lightroom (desktop) and store your photos in the cloud, then you should either get more cloud space, or you should give up on Photoshop and ask Adobe to change your subscription to the Lightroom plan, which includes 1 TB of cloud space but no Photoshop.