Received an email from Apple's Professional Services yesterday and wanted to share in case anyone here didn't receive it for any reason.
Hello, At WWDC 2020, we announced new features for the Kerberos SSO extension, including a redesigned menu extra, interface customization, and better control over the Kerberos extension setup process. We hope these new features help you continue to migrate to the Kerberos SSO extension from Enterprise Connect. For those customers who haven’t migrated to the Kerberos SSO extension yet, we are happy to announce that we will support Enterprise Connect on macOS Big Sur. macOS Big Sur will be the last major release of macOS to support Enterprise Connect. We’re aware that Enterprise Connect is not working in the current macOS Big Sur developer seed. This issue will be addressed in an upcoming seed of macOS Big Sur. We will continue to focus new development efforts on the Kerberos SSO extension. We also encourage you to begin planning for a migration to the Kerberos SSO extension if you haven’t done so already. Apple continues to recognize the importance of identity for our enterprise and education customers. Use Feedback Assistant to submit feedback for any kind of single sign-on functionality going forward and submit support requests for the Kerberos SSO extension and Enterprise Connect through your organization’s AppleCare support agreement. Sincerely, Apple Professional Services
tl;dr Enterprise Connect will be supported in Big Sur following after the next upcoming beta release, but focus will be towards development of the Kerberos SSO extension and Apple encourages moving to that quickly.