I am a Kubuntu 20.04 user. Using the disk usage manager tool, I found out that there are around 32 gb log files in my log folder under var directory. But I cannot track where the files are. When I clicked in side the folder as root privileged user, I found out that there are only 500 mb log files. I am attaching the image of my directory status.
They may be hidden files, open a terminal and list all files including hidden
sudo ls -ahlS /var/log
This will list all files, showing human readable file sizes, in list format and sort by size, largest first. Does that help?
If you find the large files that way, you can open your file manager as root and make sure you're showing hidden files to delete/manage those files.