For six months, I tried introducing purees with my son, but he didn't …

For six months, I tried introducing purees with my son, but he didn't like zucchini, only broccoli and cauliflower (the colored one was okay). But the porridge liked it, I add a little of my milk. Only the son eats a lot at once (5-20ml), I offer, but then as he wants, so he eats, I don't force feed him, just he wants porridge three times a day, especially if his sister is eating, she gets contagious appetite. Is it normal to eat porridge 2-3 times a day? I tried fruits in small doses, but now there is only interest in porridge, probably because of the milk.