I'm adding this answer more for completeness than anything else but it is possible to reduce the sweetness in a dish by using a sweetness inhibitor. From McGee On Food And Cooking:
Not only are there artifical sweetners: there are also substances that block us from experiencing the sweetness of sugars...Lactisole is phenolic compound found in small quanities in roasted coffee...In very small amounts it reduces the apparent sweetness of sugar by two-thirds.
At concentrations of 100–150 parts per million in food, lactisole largely suppresses the ability to perceive sweet tastes, both from sugar and from artificial sweeteners such as aspartame. A 12% sucrose solution was perceived like a 4% sucrose solution when lactisole was added. However, it is significantly less efficient than gymnemic acid with acesulfame potassium, sucrose, glucose and sodium saccharin. Research found also that it has no effect on the perception of bitterness, sourness and saltiness. According to a recent study, lactisole acts on a sweet taste receptor heteromer of the TAS1R3 sweet protein receptor in humans, but not on its rodent counterpart.
There is a branded blend of lactisole, sucrose and maltodextrin called Super Envision, which is the only commercially available version of this product afaik. It is used in concentrations of 0.5%-1%, e.g., if you have 500g of soup then you use 2.5g-5g of Super Envison. It can be found on websites selling Modernist cooking ingredients such as Modernist Pantry: