Xentrk
Part of the Furniture
When you have time, try routing your iMac thru Express VPN, visit a few sites and see if ads appear. speedtest.net is a good site to test on.My iPhone, Apple TV 4K, and some IOT devices are routed through the Expressvpn. And my iMac through the WAN. And Im not using Ad blockers on any devices and Ads are blocked. I have no idea how it's happening. Maybe its related to something I'm not aware of. However, I'll reboot all devices and see if that makes a difference.
To be honest even if I have to route all traffic through the VPN for diversion to work, Im cool with that.