Thanks for the reference.
I do have Malwarebytes installed, but it’s only the free version, and I can’t find any reference to that having any redirection protection.

So if I assume the special tool is Malwarebytes, then if I let Avast do its thing, is it going to uninstall Malwarebytes, or simply break it in some way. Either way it would be rather “impolite”, and almost a rouge action, but then I’m not prepared to take the risk.