User folder radically larger than sub-folders w/in it.

Most likely the data will be found in the hidden APFS snapshots which will not show up within the Finder or with any third party apps scanning the folders sizes since the snapshots are "outside" of the current file system seen by the Finder. These snapshots are usually created by backup software such as Time Machine. You can use the information in this Apple article to view & delete APFS snapshots:

View APFS snapshots in Disk Utility on Mac - Apple Support

FYI, most places within macOS will show you the "Available" space which is very misleading since it does not mean the storage space is immediately able to be used. If you look closely, many times the "Available" space will be shown with "Purgeable" space in parenthesis. Purgeable space is the portion of the Available space which will be released for use at some unknown time in the future. Free space, the space which is immediately available for use right now can be calculated from the Available & Purgeable space.

Free = Available - Purgeable

The only place I am aware of which mentions Free space specifically is within Disk Utility when you click on the "Data" volume on the left pane of Disk Utility. On the right pane immediately below the bar graph is the value for "Free" space.

So much for macOS being simple to use & understand.

Hi Joseph, yes, more maddening every year.

OmniDiskSweeper shows you the files on your drive, largest to smallest, and lets you quickly Trash or open them.

https://www.omnigroup.com/more/

Purging local backups

Please note that although this doesn't affect your remote backup from Time Machine, this will get rid of the redundancy (at least until the next Time Machine backup) that a local backup disk will provide. If you need such redundancy or are worried about the recovery of your data then you would be best served to let macOS determine when to purge these files.

Start Terminal from spotlight.

At the terminal type tmutil listlocalsnapshotdates. 

Hit enter.

Here, you'll now see a list of all of the locally stored Time Machine backup snapshots stored on your disk.

Next you can remove the snapshots based on their date. I prefer to delete them one at at time. Once my "System" disk usage is at an acceptable level, I stop deleting but you can delete all of them if you want to reclaim all of the disk space.

Back at the terminal, type tmutil deletelocalsnapshots YYYY-MM-DD-HHMMSS , where will be one of the dates from your backup. This will be in the form of xxx-yy-zz-abcdef. Try to start with the oldest snapshot.

Hit enter.

Repeat for as many snapshot dates as required

http://www.thagomizer.com/blog/2018/03/27/cleaning-up-time-machine-local-snapshots.html

tmutil deletelocalsnapshots / # deletes all the snapshots

Thanks to BobHarris file sizes, Applications -> Utilities -> Terminal:...

sudo du -hx | sort -h 

sudo du -hx ~/| sort -h 

Hi!

Thanks for the heads up. Not easy to understand, that's for sure.