This would probably false positive every CGNAT IP, or am I misunderstanding something?

I think "residential proxy" in this context is "AI scraping bot/pay Netflix at Indian price VPN exit node", not just an IP with NAT on outside.

If there were people under the same CGNAT with someone running one of those exit nodes, then that's not a false positive.

I think CGNAT is a type of residential proxy.

Hidden from the user and provided by the ISP

CGNAT isn't a residential proxy

Yes, it did and it does.