I’m certainly not an nutritional expert but I don’t believe combining breakfast and lunch into one large meal is a good way to go about things. I think most people accept that eating smaller meals more frequent is better than fewer large meals.
In contrast to you, my target without exercise is 1600kcal so on those days I eat a ~400kcal breakfast, 2x 90g of Huel (lunch, dinner) and ~400kcal in snacks/fruit. On days I exercise I do the same but with 3x 90g of Huel with the extra one coming an hour or so before I exercise.