App Tracking Prevention
DuckDuckGo has this great feature where it essentially runs a VPN but it blocks traffic from devices from being sent out. So, when a data tracking engines (e.g., Google, Adobe, Amplitude, Branch Metrics) attempt to send personal data from your device DuckDuckGo blocks it.
If Proton incorporated the same concept into the VPN then it would be an even more effective product!
Proton User commented
It would be nice to make all app tracking visible just like DuckDuckGo because that's made me upgrade to Proton Unlimited (Netshield) With making this visible, it would be easier for the user to delete certain apps which trying to scrape as much data as possible