PRA - Email based MFA

Hello , I see there is only TOTP MFA option in PRA . We are using PRA for external Vendor access where the accounts are quarterly reviewed but as the number of vendor grows , manual errors might increase. Also as the review can not be made more frequent , there is a possibility that Terminated vendor user still has access as they know their PRA login password and have TOTP MFA configured using a personal mobile device. These user identities are in Active Director as well as PRA internal DB. Is there any way to implement email-based MFA so that terminated user will immediately lose access as they wont have access to company email ?

I see Radius auth and OKTA can be used both have separate trade-offs