Why is my hard drive SSD is showing double the space used than the actual files on the drive?

I'm swapping my second HDD for a new SSD in my MacBook Pro running Ventura. Both drives, old and new, are 1TB. Old drive is formatted Mac OS extended (Journaled), new drive was just reformatted APFS. I only copied files from my old drive, about 300GB to new drive. New drive is showing over 600GB used, 300GB free. When actually looking at the file content of the new drive by getting the storage used for each of the folders, there's only 300GB of files in those folders. Any idea why this would be? New drive was freshly reformatted before I copied the files.