Alcohol to get a “soda-like” profile?

I recently made the Nuka-Cola recipes from the Fallout cookbook in anticipation for the show. I really enjoyed the flavor and thought I could use the syrups in cocktails.

However, I still want a Nuka-Cola feel to it. My local bar has a take on Nuka-Cola classic and Quantum which both use whipped vodka, so that’s where my mind immediately went to. I was wondering if there were any better liquors to use though.

To be clear, I want the flavor to come mostly from the syrups and I don’t want the alcohol to take away from or overtake the flavors of the syrups. Something that adds to the cola/cream soda effect is what I’m looking for.