Cook and stir onion and garlic in a skillet over medium heat until browned, 4 to 5 minutes. Combine onion mixture, hot water, and chicken bouillon in a bowl.
Place roast is same skillet used for onion mixture; cook over medium heat until roast is browned on all sides, 4 to 5 minutes.
Place roast in a slow cooker and drizzle olive oil over top of roast. Arrange potatoes and carrots around roast. Pour broth mixture over roast; add butter, bay leaves, sugar, salt, and black pepper. Pour wine over entire mixture.
Cook on High for 4 to 5 hours. Change setting to Low and cook for 2 to 3 hours more. An instant-read thermometer inserted into the center should read at least 145 degrees F (63 degrees C).