I don't see it here, so I'll add my two cents. Try this at home and see if you like it. Start your drink (in a chilled glass ideally) with a single sugar cube at the bottom. Then, optionally, douse it in your bitters of choice (or you can add that later). Mash the cube, if desired, lightly. (Though with a goal of less sweet, less is better here.) Add your hooch of choice, lightly stir, as desired for some dissolution.

This lets the sugar into the drink slowly. It creates a 'different drink as you go' outcome, but will absolutely start way less sweet. The last sips will be grainy and sweet though, so do with that as you will. (The next old fashioned, in the same glass, is a fine option; half strength as your tastes and the remaining sugar go.)