Hi @Rune-KH,
As far as I am aware you can't check for the status of the flag within the When an email is flagged (V3) trigger action .
But maybe you can workaround this by using the following approach: Enable the ToDo-Outlook integration, https://support.microsoft.com/en-us/office/using-microsoft-to-do-with-flagged-email-from-outlook-f90c37b0-4453-4756-a6d5-e2ef8d33b395.
When you enable this, every flagged e-mail gets tracked in the Flagged Email ToDo list. The benefit of this integration is that whenever a flag is set to completed, the task is also set to a completed status. You can use a trigger for ToDo to track completed task and then find the linked e-mail and move it.
Below is an example of such a setup.
1. Add a trigger When a to-do in a specific folder is updated (V2) action. Connect it to the Flagged Emails To-do list.

2. Assign the following trigger condition in the settings of the trigger
@equals(triggerOutputs()?['body/status'], 'completed')

3. Add a Move email (v2) action, configure your move folder and use the following expression for your message id
triggerOutputs()?['body/linkedResources']?[0]?['externalId']
