Unfortunately it is not possible to do it with the built-in dropdown component.
The reason is: this component is a kind of list and it requires a connection to a collection to take values from.
I agree that “regular” dropdown with fixed options could be a very useful component. Maybe some component developer will create it eventually.
Maybe @CH_Team can improve its current implementation. I find it very unpractical , and probably it is bad practise as well, to create a database table just to have 6 static values in it.