You can use tags to create filtered views of your listings to display shared characteristics. When you filter by a single tag, you are most likely to get multiple results. However, when you add multiple tags to your filter, you may get fewer results, as fewer listings have them in common.
This behavior is by design, and is because the filter checks for listings that have all tags you added to your search, rather than providing a list of all the listings that have one or some of the selected tags.
This is due to the usage of AND logic the Guesty system is using to display listings with tags, and an OR logic the system is using to display multiple listings.
As a workaround, start your search by adding one tag, and add more tags to filter your results further.