Talk to Pediatrician on Baby Not Gaining Weight

My baby is 8 months old and he doesn’t like to take milk. He is exclusively formula fed (Meiji) but always have been fussy while taking milk and his milk intake has been v low since the time he is born. After consulting a Paediatric I started weaning him when he was 4.5 months old. He has been underweight throughout these 8 months whereas birth weight was 3.5kg. Now he has stopped taking milk and I tried a lot but he just doesn’t want to. I give him yogurt, rice and fruit cerelac , all seasonal fruits and vegetables purées, sabudana, sooji ki kheer, rice kheer cooked in yakhni with potatoes, oats cereal with banana and also add desi ghee in his food. I’m giving all of this according to a diet chart provided by his paediatrician. He takes 4 to 5 meals a day but just not gaining weight according to his age or birth weight. Currently he weighs 6.9kg. He is also teething now a days. He eats semisolid food happily but just doesn’t take milk and I do add milk in his food while prepa