I’ve been thinking about this and there could be a solution to ensure that all of the terms in a taxonomy are always included/selected for the filter. This could be done with an acf/load_field filter. Export the taxonomy field to php to get an idea of the settings for the taxonomy selections. In the filter get all of the terms in the taxonomy and populate the acf field setting with the correct values. This way, if a term is ever added to the category it will be automatically added to the list.
