OIDC is the only way to get proper 2FA into all services without adding tons of friction. Friction reduces acceptance and usage of 2FA.
Every service that puts SSO in an enterprise tier is a security risk and shouldn't be touched with a 10 foot pole.
Go ahead and put Kerberos and SAML and maybe even LDAP SSO in Enterprise tier, but if you put OIDC in enterprise tier, you're responsible when your customers will get inevitably hacked.