Welcome to the community and thanks for the feedback, @Jeffrey_Garrett.
As you noted, you can access the volume control by tapping to expand the details. It’s on our hitlist to add a Volume / Level control tile, but it surprisingly hasn’t had as much user-interest as we expected, so we’ve prioritized other highly requested features first.
Update: Check out the new Vertical Range Input custom tile!
Alternative Approach using Variables
In the meantime, you might be able to use Variables to approximate what you are looking for. You could setup a new Number variable then setup a rule such that anytime the variable changes, use it to set the level of the physical speaker:
Note that when using a Device action in a rule, you can tap the <> variable icon to use a variable as the value of a command argument:
You can then add the Number variable to your dashboard and enable the Quick Adjust in the Tile Settings which provides up down buttons for quickly adjusting the value:
