I am going to copy your steps and keep them to use. But as far as looking at all the options, I wouldn't know what I was looking at. I think that leaving it set on third party apps is a good idea. I am just hoping that those 3rd party apps haven't wrapped themselves up in something I need and that would go out in the trash should I get rid of them. That's my main concern.
Your concern is legitimate and understandable but there are three built in protections:
- The previously mentioned SIP is Apple's contribution because it prevents third party apps from modifying system files so they are highly unlikely to be involved
- Anything likely to be used by more than one application will almost certainly appear among the "Further files"
- CleanApp provides the little horseshoe icon to indicate the likelihood that the indicated file or folder is associated with the selected app. If it is completely filled in it is certainly associated with the app. If it only has a small corner filled in it is questionable
In my experience a low probability usually indicates a file or folder used by two apps from the same developer. This is common among Adobe and Miorosoft apps, less so with apps from other developers.
If you leave some files or folders it is likely they will be picked up in one or more of the "spring cleaning" routines.
