Suffering from smelly farts after dinner since last 4 years

Suffering from smelly farts since last about 4 years. They start in the evening post dinner almost daily. i have done the following - 1. Ruled out ciliac disease via test 2. Doctor has given various antibiotics and probiotics. Secnidazole has helped for a few days after a 2 tablet dose, but problem restarts after a few days 3. i also had a colonoscopy done, which was clear 4. This happens no matter what i eat Please suggest some line of action

Lifestyle changes might help. Start walking.