I tried and it doesn’t update, even after a clean reboot with no browser open whatsoever. However I did find another entry in the Firewall that comes up right on boot, which is a service called MS.Edge.Webview2, which seems to be triggered through the Teams App. I’ve now completely uninstalled Teams, and after a fresh boot the ad (or “media control”) seems to be gone now. Guess I’ll be using Teams from my phone or via browser in the future.