How do I filter my list query for "All" items, not just specific selection.

Hi,
I have a dropdown that I want to use to filter the list.
I am doing the following:

1. Create a dropdown with values (All, Red, Blue, Green).

2. I have multiple list items with a field called Color and this field has values Red, Blue, or Green).

3. When the page first load, I want to show items with all colors.

4. When the user selects Red from the dropdown, then only show red items.

5. If user clicks "All" then I want to show all color items.

I followed this tutorial but my particular usecase is not covered here: https://www.youtube.com/watch?v=Xw_Axw-GIkE

When I try to select "All" from the dropdown, I get an empty list because the code tried to search for a value of "All" in the Color field which does not exist.

Does anyone know how can I overcome this constraint?