From LDAP to standalone: remove users

We have a server with around 1000 LDAP users.
Now I want to make this server standalone, removing all the LDAP users.

The problem I am facing:
There seems to be no way to remove these users and their data.

While connected to LDAP, the users can’t be deleted.
If I remove the LDAP connection, the users are unknown.

Ans ideas?


Nextcloud version (eg, 18.0.10):
Operating system and version (eg, Ubuntu 18.04):
Apache or nginx version (eg, Apache 2.4.25):
PHP version (eg, 7.2):