Using the nodes from Think Parametric / Archi-lab package you could override elements by Category instead of having to create a View Filter. There is a limited number of filters that can be added to views and I usually reserve those for more complicated things than just making sure that all my walls have a “Fill Color”.
If you prefer to manage View Overrides with View Templates you can do that as well just by overriding a Category in a View Template like so (again using the nodes from Think Parametric + Archi-lab):
