And how do you get those residential IP addresses?

Well, you just need people to install your browser extension. Or your proprietary web browser. Or your mobile app. Or your nice MCP. Maybe get them to add your PPA repository so they automatically install your sneakily-overriden package the next time they upgrade their system.

Anything goes as long as your software has access to outgoing TCP port 443, which almost nobody blocks, so even if it's being run from within a Docker container or a VM it probably doesn't affect you.