We have a SharePoint 2019 farm, our extranet is implemented on SharePoint. We want to develop a SharePoint portal/site with MFA applied for limited users with or without AD accounts. Can we have an extranet with existing sites requiring no authentication as well as a private portal with MFA implemented for limited audience?
What options do we have other than ADFS? With ADFS what is required to setup the environment. Without ADFS is it possible to go with custom Form Based Authentication with MFA for SharePoint 2019 Extranet?