Scratch Disk Not Correct Size

I have tried to open up Photoshop but it keeps saying Scratch Disks are full. So, I have attached a 2 TB Sandisk Extreme (with 1 TB remaining) APFS-formatted external SSD to my 2020 M1 Macbook Air in hopes of using it as a scratch disk. It worked for a while but now, Photoshop seems to think that the size of the SSD is the exact same as my internal hard drive. I have attached below a screenshot of the issue as well as a file structure of my SSD, which I think maybe the issue. Does anybody know what the issue might be?

(the SSD's name is "Laptop")