11 months old not eating solids

My son is only breastfeeding since birth. He started eating solids when he was 6 months. He mostly played with the food rather than eating it and I thought it was normal. However, I also thought it would get better. It didn’t :( For the last month he refuses to eat anything solid, either purée or mashed or whole. He went from 24 percentile to 19 and he hasn’t grown in height for the last 3 months. Friends and family are telling me to reduce breastfeeding or start supplementing with formula so that he gets more calories and iron. I am confused 🤷‍♀️