I only put water, kosher salt, garlic and dill to pickle cucumbers, never vinegar. But my recipe is 19th century, handed down in my family. Maybe modern Ukrainians add more ingredients, including vinegar?
Borsch should be a good hangover cure. According to wiki-fitness.com/best-worst-hangover-food-list, Beetroot has an important quality of detoxifying the liver, as it contains 95 % water and 05 % sugar. And we know that hangover is due to the excessive secretion of water from the body, so the intake of the beetroot automatically starts rehydrating the body and that way it reduces hangovers.