A good set and forget option for the non-tecnical or those that can't be bothered is https://www.iantispy.com, basically just does it's thing and doesn't nag to upgrade.
Yeah nice one... Little Snitch is made in Austria and has email for support. The one I suggested is made in Australia and also has email for support. They are both offered by registered companies with their relevant registration numbers shown on their respective sites. Both have a privacy policy and a terms of service. Both "have complete control of your system" (whatever that even means, neither requires elevated privs). Seems pretty standard. iAntiSpy is also on the App Store, so there's that too.
politics aside, based on public information it feels like the main difference between this and all the other metadata-type systems in place is the centralised ability to downgrade connections?
I think the magnitude and extent of the integration is a big difference. The cellular and internet providers essentially work for the government at all times.
macOS and 3rd party caches are out of control, so much so that I made an app for that about 12 years ago. It's freemium but the cache/3rd party quick clean is totally free and I don't really nag - https://www.iboostup.com or the App Store; unfortunately adware is becoming a problem on macOS too so it handles that as well. Users that opt in to stats have collectively freed petabytes of data. Requires El Cap or above, I update monthly so always supports the latest.
update: just released v10.5 that removes this huge wallpaper cache as part of Quick Clean, among other things. More info https://www.youtube.com/watch?v=H_M5GdnncxA - about to submit it to Apple.
