Currently, you can only login as one email, and setup multiple workspaces under that single email. If you're a freelancer working for multiple companies, you would either have to create different workspaces under that single email, OR you would have to logout then log into the other email. Slack, Notion and other tools already allow you to separate the workspaces at the email level. They allow you to have multiple workspaces for different emails so that you can easily switch between them without having to logout, and without having to mix your workspaces into one personal email address.