I mentioned in the group yesterday that I would post the single click opt-out build smart campaign that should be a part of your subscription management campaign. The setup is pretty simple:
Smart list is a trigger based on clicks link in email, with the link to a unsubscribed 'we wish that you'd come back' landing page.
The flow is a change data value action for both unsubscribe and marketing suspended to true.
Happy to answer any questions you have!