Anyone who cares about ad blocking should not be using any Chromium based browser at this point, but isn't this the sort of tool you'd use at a network or virtual network level?

There's no reason to let applications on your device bypass your own network settings - and this is something we probably need to start accommodating in Linux distros to start with (specifically: disabling all the weaponized E2E encryption that vendors are using, and forcibly MITM'ing it with keys under the users control).

Network-namespaces should make this eminently possible - launch the user's entire environment into a network namespace which can only speak to "user rights" networking stack.