File Size reporting vs "size on disk" (cloud services render disk usage reports useless)

I've used Apple machines since the 80's (Apple ///) but I just now discovered file "Size" vs "size on disk" (get info). I first noticed that when using Dropbox and setting storage as "Online Only" (Smart Sync) the "File Size" info remained the same even though it was no longer on my Mac. If I "Get Info" the "File Size" will be the normal file size but the "size on disk" reflects reality, that is, it's almost zero as the file is not on disk but remote. File size in finder also shows the cloud size, not what is on local disk.

The problem? Use the Finder Search tool to find large files (for disk maintenance and such) and the "un-real" "Disk Size" is reported, not the actual "size on disk." I checked a couple of Disk Util's and they also reported the cloud "Disk Size" and not "size on disk."

Thus, if you were to have most all contents of a disk "Online Only" (Dropbox) the disk Get Info and Util's would report the disk full of data (size) when in reality it could be empty.

Does anyone know of a utility that reports BOTH "Disk Size" AND "size on disk?"