mac os big sur upgrade

I tried upgrading to Big Sur from Catalina 10.15.7, and the download took several attempts saying "the update could not be verified". I finally got the 12 GB+ file to download, but when it tried installing it threw the error "an error occurred while installing the selected updates". After several times trying the install it finally threw the error: "big sur operation could not be completed due to disk space recovery error 1". I then deleted the download because it was taking up all remaining disk space on my hard drive.

Before I attempted to update I had ~19 GB free space, and now this is down to ~13 GB. So I now have 6 GB less space available and no OS upgrade. How can I address this?