There is no automated user deletion. That'd be far too easy to make a mistake and suddenly wipe out your database of users. Users can delete themselves using CB Privacy and its Delete Me field. As far as deleting them after 5 years of no subscription you can simply filter CB > User Management now and again and delete them manually.

There is no automated solution. It's too dangerous. You could probably force something using CB Auto Actions and CRON, but I strongly advise against it. One mistake and you've purged your entire database of users. We'll likely never implement something like that. It's the same reason CB Auto Actions does not provide an auto action type to delete users even though it's a simple function call. It's too easy for one mistake to cause a significant amount of damage. We've an obligation to protect our users; including from themselves, sorry.

CB Auto Actions performs actions on a trigger that something has fired and there is no trigger fired simply because a users has been inactive for X years. The only way to do what you're wanting is to use Internal Users trigger then setup CRON to execute the Internal Users URL regularly, but this will loop the action through every user of your site and is extremely heavy to do (it has no pre-filtering functionality or batching at this time).

Alternatively you can set Triggers to None then use CRON to execute the action directly (URL to do this under Global tab of your auto action). You'll need to then use a Code action and set Method to PHP. Next you'll need to code your entire implementation of finding users who have been inactive for 5 years then delete them or I suppose modify their profile data.

We do not have functionality for this out of the box (e.g. 1-2 clicks) for either of the above cases and likely never will simply because it's too dangerous of a feature to provide. Joomla may provide something like this in their privacy component planned for Joomla 3.9 and if so we'll integrate with it, but my guess is that feature again won't exist due to how dangerous it'd be.