Speech Delay. On? should we be worried?

My son is 2 years 6 months old. He weighs about 11.50 kg now and is pretty active. He doesn't eat much. We are worried about his speech delay. He is not saying any words. He is only blabbering and trying to make sounds like 'appa' 'oooo' 'abba', 'mamama', 'dedda', etc. He screams, points to objects and says nothing else. Reacts when we call his name but doesn't follow instructions. Plays with all his toys and he knows how each of his toys works. When we teach him words, which are in fact very few, he only repeats the first syllable that too after repeated prompting. We have shown him to a peadtrician, ENT and psychiatrist. They say it's normal. We have also done BERA test and result were normal. Doctors have advised us to reduce screen time for the baby and train him at home. As prescribed by doctors we are giving him omega 3 syrup and Iron supplements. Is there anything we are missing out on? Should we be worried? Is there any other specialist that we should consult. Kindly guide us.