Children have a number of peculiarities of taste perception: they prefer sweeter, more salty, more sensitive to bitter, and to a greater extent avoid food with unknown taste. The rejection of vegetables is most likely due to the fact that the taste and smell are unfamiliar to the child, in addition, many vegetables are bitter. Since kids prefer everything sweet, try starting with sweeter vegetables, or you can add some sugar to a vegetable puree, for example. You can try not tomatoes, but tomato products: juice or sauce. Adding small amounts of vegetables to the meals the child takes may work. When the smell and taste of the vegetable become more familiar, the child will most likely stop avoiding it in its raw form.
The adoption of certain foods by the child, in addition to genetic and other reasons uncontrollable by us, is primarily associated with the mother's diet during pregnancy and breastfeeding. The substances responsible for the aroma of many vegetables and fruits can penetrate the amniotic fluid and breast milk (for example, even while in the womb, the baby can smell the garlic that the mother ate at lunch [nih.gov]). Accordingly, even being breastfed, the baby "gets acquainted" with some products of the adult diet and in the future will perceive them better, they will not be completely new to him and he will consider them safe. (This mechanism is well known for carrots, for example nih.gov). Food neophobia (fear of new things) is primarily an evolutionary defense mechanism against poisoning, since unknown foods can contain poisons, and those that we have already tried are definitely safe.
We need to start cooking them deliciously. 1. Try making tomato or cucumber juice. 2. Make tomatoes with mozzrella and fly the whole thing with balsamic vinegar.