Welcome to VMTN. :-)
Do you have an active snapshot on this VM ? That could explain the 752 GB in use. Remove the snapshot and consolidate the VM if the snapshot is not required.
Hello and thank you
First thing I did was to delete all snapshots.
Any other suggestions?
Can you try consolidating the VM and see if it helps.
Are you referring to "Consolidate disks" under "Snapshots" ?
Before running above I followed this guide Shrink guest on hosted platform - VI-Toolkit
in Ubuntu I ran cat /dev/zero > zero.fill;sync;sleep 1;sync;rm -f zero.fill and waited to complete.
Then, after almost 5hrs of running "Consolidate disks" task option for this particular VM it shows this https://prnt.sc/n6py7t
which is an improvement but df --human in Ubuntu shows that out of 400GB only 176GB is used?