I've been told the only way to track Unsubscribes in email metrics is to use the official Unsubscribe link: {{email.unsubscribe_link}}

We want to track Unsubscribe % in our email metrics of course... however, using this link not only immediately marks “DND Email Channel = True” but I'm told ALSO marks it in the backend in MailGun.

This makes it incredibly difficult to re-subscribe people. We were going to just create Workflows for certain form submissions that will re-subscribe people when they fill out the form, as we can just make a step in the Workflow to mark “DND Email Channel = False” ... but that won’t change it in MailGun and so they will still be unsubscribed even though it shows otherwise in the HL Contact record!

In database functionality, there should always be "one version of the truth". Tracking unsubscribes in two different systems seems to lead to a lack of visibility and makes functionality like re-subscribes difficult if not impossible.