Rename all previous LDAP users to prepare SAML integration

Hi, after a important migration from owncloud 8.2 and upgrade to Nextcloud 14, I am now searchinhg a way to move from LDAP auth to SAML auth.
With my test instance, I tried to find a way to use SAML auth with Groups and account provisioning from LDAP.
Previously, my LDAP settings were using UUID (default conf) and, and if I want to use SAML auth with Groups and account provisioning from LDAP I need to move to UUID set as UID (In the LDAP settings, in the Expert tab, there is an Internal Username Attribute: field. In my case, I set this to uid. ).
It works well for new users, their data directory is created with uid.
But the problem is with my 200 users previously created with UUID :

  • Is there a correct way to move their data directory generated with UUID to uid ?
  • Is there a correct way to change in all the DB UUID to the new uid ? (to recover share files and directory, etc.)
    I saw the “Username-LDAP User Mapping clearing” option, but it just clear the mapping and does not do a new mapping.
    Any idea to prepare this migration ?