How very challenging and worrying for you.
Years ago, a method discussed was for toddlers to choose their own food and they would balance out, even if they chose a particular "not good" food over others for a while. The idea was to leave small bowls of a large variety of foods on a low table and let the toddler take what they wanted, when they wanted and how much. They found that they quite soon they self regulated, ate enough and the pressure was off them from being in the spotlight.
For some children, the persuasion to eat can almost stop them. Also, any conversation about them that they can hear. It can put real pressure.
I do wish you well