In the LDAP configuration you can change the internal username in the expert tab. You might need to clear the mappings.

There are several things you must know before changing this:

• Changing the attribute isn’t supported once the system starts rolling. DO NOT change it in production.
• You might need to clear the stored mappings. Again DO NOT clear them in production since all the data associated to those users will be lost
• It’s your responsability to keep the attribute unique in the whole system. The object uuid is usually used for that. Expect issues if this isn’t respected.

I don’t know what options the 2FA system has, but I’d recommend to check them and try to solve it from there. We’re recommending to use the default uid (objectuid) because it’s guaranteed to be unique and give less issues.

Source: LDAP-User created with uid – Server – ownCloud Central