The ethics of these free VPNs and hidden proxy SDKs are very questionable. But they are crazy profitable for the proxy providers running them so unlikely to go away.
Bright Data operates a service where you agree to allow your network to be used in their proxy system. In return, they give you a small amount of money per gigabyte of traffic. https://earnapp.com/
There is a community of people who use these passive income apps for some pocket money. It's not too good to be true, but they pay you so little compared to how much they make from you. For example, they pay $0.60/GB for united states traffic, and charge approx $15.00/GB for residential proxy use on the Bright Data network.
I mentioned this SDK, EarnApp, in my other comment. I am a shady web scraper that uses these services when necessary. The real answer is, STOP USING IP addresses for reputation scanning. With ipv4 exhaustion and CGN, this is an inevitable outcome anyways.