Is Cisco Duo the MFA factor to use when not authenticating through Okta?

As a first pass we just want to refactor our in-house 2FA implementation by using Okta’s MFA factors. It looks like the Cisco Duo factor is the one to use since it allows me to bulk upload existing users from our system / allows for self-registration by end-users. Is that a correct assessment or are there other factors I should look at that allow the primary login handler to be our already existing authentication implementation ?