I feel this is a very long shot as for most, the few teaspoons of sugar in a good loaf of bread you will find at an artisanal bakery is negligible especially considering that bread is mostly carbohydrates/sugars.

However, I just checked my recipe book and the only recipes for bread I have that do not require sugar are sourdough.

I feel calling around to bakeries and asking if they add sugar into their sourdough bread will be fruitful. Barring that get some starter and get baking!