@konrad.sopala can this be achieved using actions?
For example, could a custom parameter be passed to the /authorize API to signal which factor to enroll, such as &mfa-enroll=otp or &mfa-enroll=phone?
https://community.auth0.com/t/passing-custom-parameters-to-auth0-actions-from-applications/134319
Then the action would look for event.request.query['mfa-enroll'] === 'otp' in the action and execute:
api.authentication.enrollWith({ type: 'otp' })