I guess when Workspace is no longer being paid for, Studio locks you out of your Workspace stuff. We have an article about moving Workspace content out of Workspace, but I suppose that’s a moot point for you now.
It seems like this is a tricky edge case - I think your business email will be connected to this defunct Workspace situation now. You’ll need to use a different email in order to start using the free version of Looker Studio.