2g total sugars per cup, its not very high at all.
FYI I wouldn’t worry too much about oat milk as the carbs are the wrong form. Its much higher in total sugar (7g, still not much in the grand scheme of things) but the remainder of the carbs are in starches which won’t impact tooth decay because you don’t have the right enzymes in your mouth to break those down to sugar.
All carbs that are not fiber are ultimately broken down to one of three sugars in the gut. Complex carbs are slow sugar, simple carbs are fast sugar.