How can I join computers to Active Directory without using the account that created them?

The account that creates or prestages the computer object does not have to be the account used for the domain join. Delegate the appropriate permissions on the target OU to a separate account, then use that account to join the machines. There is no special workaround required for this scenario.

If the computer object is prestaged, newer domain-controller scenarios can also support joining without an interactive user account, depending on the Windows and domain functional-level requirements. In most cases, though, prestaging plus narrowly delegated join permissions is the simplest supported design.

Offline Domain Join is another option. You generate the provisioning data from a system that can access Active Directory, then apply it to the target machine separately. This keeps the joining device from needing direct connectivity to a domain controller during the join, although it requires additional planning and does not replace proper permissions management.

You can prestage the computer accounts in Active Directory and use the computer-account creation wizard to specify which user or group is allowed to join those machines to the domain. This is useful when you want a tightly scoped operator account, including for non-Windows systems.

A regular domain user can usually join a limited number of computers by default, while delegation can grant a specific account permission to join more machines without making it an administrator. For stricter separation, delegate only the required rights on the relevant OU instead of creating a temporary OU-admin account.