On the main Thunk page, click your user icon in the bottom left of left frame (likely just a circle with the first letter of your name)
Click My account
Click the Connections tab
Clicking Enable More Permissions brings you to a login screen for Google. If any login is required, it should be through Microsoft, not Google, since this is a Microsoft 365 connection.
Additionally, if you click Add new connection and select Microsoft 365, you also are brought to a Google login page.