Using Classic Outlook on Windows for personal email, calendar, and contact management
Hello Cynthia,
Based on your description, I did a lot of tests and research on Outlook Quick Steps with "Done", first as far as I know in the "Done" quick steps it contains Moved emails to a folder, mark as complete, and mark it as read. However, for the second action "Mark as complete" it belongs to Task feature in Outlook, generally for non-Exchange protocol based email accounts don't support to sync Task related services, so this action is not available for non-Exchange accounts.
Since you are using Google WorkSpace email account in Outlook Client, this kind of email account doesn't support Mark as Complete feature belongs to Task by default, so the "Done" quick step is not available. By the way, if you have any other Exchange type account (ie outlook.com or Microsoft 365 business email account), you will find the Done listed in the ribbon, thanks. For you current scenario, if Mark as Complete is not required to you, you could try to manually create a new quick step with actions "moved to xxx folder" and "Mark as read“ in your Outlook as workaround, thanks.
Your understanding and patience will be highly appreciated.
Best Regards,
Oliver