how to search broadly and not just within a CPT

On my main page, the search bar has a drop down menu for all CPT categories I have added. However, this dropdown forces you to select a CPT and then you enter a search keyword that will only search for listings within the selected CPT.

Is there a way to search broadly across the site and ALL listings without being forced to pick a CPT?

For instance, in the CPT category dropdown, it would just be a blank option so the user can just search any keyword without having to first select a CPT.