NC13 webdav windows credentials

Dear support,

I have NC13 installed on my server. Authentication is via LDAP where user must supply name.surname ad username to be authenticated.

Some usersmap their nextcloud via webdav to their windows pc. These pc are connected to an active directory and to authenticate they supply name.surname@domain as username.

In this way they cannot automatically have their nextcloud space mapped.
Is there a way to truncate @domain before user authentication on the server and avoid users to insert the password twice?

What file should I modify to do that?

Thank you very much,