Actually it's a good thing that Netflix does support IPv6 for this. As any device using Netflix via IPv6 from your ISP would likely correctly be protected as not a VPN or proxy.
The problem is the ISPs that deploy CGNAT without also deploying IPv6 is ridiculous. They are directly affected by the death of IPv4 yet will not deploy IPv6, to me that is unacceptable.
Unfortunately as well you have devices such as Roku who still refuse to support IPv6 at all, so even if said ISP deployed IPv6 at least users using Roku would still be in the same boat.