I have also a problem with avast free antivirus.
I have tried to uninstall it with the avast removal tool but their are still files remaining.
Windows defender firewall is still under the control of Avast.
How do I uninstall these files?
The free version of Avast doesn't have a firewall and certainly doesn't control the Windows firewall.
Any files remaining after using the removal tool can be removed manually. You can also simply leave them.
They don't interfere with any other programs.