This behind a Google Account login—which, if you have the grandfathered “Google Apps for Your Domain”, or just a Gmail address, you will have—is the beginning. I haven’t received my email yet, but this is coming for sure:

“If you have the G Suite legacy free edition, you need to upgrade to a paid Google Workspace subscription to keep your services. The G Suite legacy free edition will no longer be available starting May 1, 2022. Starting May 1, Google will seamlessly transition you to Google Workspace, which you can use at no cost until July 1, 2022.”