My MacBook Pro uses 194 Go of system space ...

Thanks a lot, leroydouglas ... here is what I get with the suggested commands :

diskutil list internal
/dev/disk0 (internal, physical):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *500.3 GB   disk0
   1:                        EFI ⁨EFI⁩                     314.6 MB   disk0s1
   2:                 Apple_APFS ⁨Container disk1⁩         500.0 GB   disk0s2

/dev/disk1 (synthesized):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      APFS Container Scheme -                      +500.0 GB   disk1
                                 Physical Store disk0s2
   1:                APFS Volume ⁨Macintosh HD - Données⁩  378.3 GB   disk1s1
   2:                APFS Volume ⁨Preboot⁩                 600.7 MB   disk1s2
   3:                APFS Volume ⁨Recovery⁩                1.1 GB     disk1s3
   4:                APFS Volume ⁨VM⁩                      20.5 KB    disk1s4
   5:                APFS Volume ⁨Macintosh HD⁩            15.8 GB    disk1s5
   6:              APFS Snapshot ⁨com.apple.os.update-...⁩ 15.8 GB    disk1s5s1

here I guess we can only see my 500 Go HDD with the 2 volumes but not sure if we can see something suspect ... as a reminder I only have really like 170 Go of personal data (documents, pictures, ...), as far as it is synced with OneDrive and I see this win Onedrive like 170 Go used out of the Terabyte I have.

with the second command, it looks like "Library" is what is taking the most ... not sure it is normal ???

177 Gb !!

sudo du -h -d 1 ~/
11G /Users/currentuser//Music
113G /Users/currentuser//Pictures
 65M /Users/currentuser//Desktop
du: /Users/currentuser//Library/VoiceTrigger/SAT: Operation not permitted
177G /Users/currentuser//Library
4,0K /Users/currentuser//.cups
8,0K /Users/currentuser//.bash_sessions
  0B /Users/currentuser//Public
4,0K /Users/currentuser//.ssh
 12G /Users/currentuser//Movies
3,0M /Users/currentuser//Applications
  0B /Users/currentuser//.Trash
904K /Users/currentuser//Documents
144K /Users/currentuser//.anydesk
3,3G /Users/currentuser//Downloads
8,0K /Users/currentuser//iCloud Drive (archives)
316G /Users/currentuser/

Is it possible you help from there ?

Thanks a lot for the help so far !

the output of the third command is far too big to copy / paste it here ... so I have only taken the lines where folders could be accessed and removed the lines where folders could not be accessed "Operation not permitted"

sudo du -h -d 1 /
585M /usr
4,7M /bin
2,0M /sbin
7,3G /Library
379G /System
5,1G /private
  0B /.vol
328G /Users
 18G /Applications
200M /opt
4,5K /dev
  0B /Volumes
  0B /cores
738G /

Many thanks for the help so far !

P.S. and I found what is taking so much time in the mean time ... in the Library folder, there is something about by personal data files (I told you my personal documents were around 170 Go ...) in OneDrive/Documents sync ... which is the folder on my MacBook where I store my personal files and it get synced with Onedrive ...

sudo du -h -d 1 /Users/currentuser/Library/Group\ Containers/UBF8T346G9.OneDriveStandaloneSuite/OneDrive.noindex/OneDrive
155G /Users/currentuser/Library/Group Containers/UBF8T346G9.OneDriveStandaloneSuite/OneDrive.noindex/OneDrive/Documents Sync
7,1G /Users/currentuser/Library/Group Containers/UBF8T346G9.OneDriveStandaloneSuite/OneDrive.noindex/OneDrive/Camera Roll
 32K /Users/currentuser/Library/Group Containers/UBF8T346G9.OneDriveStandaloneSuite/OneDrive.noindex/OneDrive/VTO2000 motion snapshots
162G /Users/currentuser/Library/Group Containers/UBF8T346G9.OneDriveStandaloneSuite/OneDrive.noindex/OneDrive

But I guess those have nothing to be done in a Library / Group Containers right or ... ?

Many thanks so far !