iOS - Can I "white label" certain apps not to be auto-offloaded?

I can find no option to whitelist individual apps, which is a great idea. It seems to be all or nothing. I've taken to removing a lot of apps I rarely use manually, foregoing this utility, unfortunately.

Apple's official wording states: Automatically remove unused apps, but keep all documents and data. Reinstalling the app will place back your data, if the app is still available from the App Store.

Perhaps you should write to the developer of CCTV Viewer if the setup/pairing data is not retained when the app is off-loaded and then re-installed.

You should also go to the Apple Feedback site for iPhone and make a feature request. You won't get any reply unless you provide your email address, and they have further questions, but at least it'll get on their (very long) list of enhancement requests.