Well done for identifying the issue and trying to tackle it. As you have identified, delivered food, alongside bought lunches, coffees etc are very expensive and often something to look at when budgeting.
For alternatives, even supermarket equivalents like pizzas, curries, meal deals will be cheaper, so you could try those for the 'too tired, CBA, no time to cook' nights? Or have quick, easy food like omelettes, egg or beans on toast etc.
We always have a stock of canned lentils, pasta sauce jars (Heinz do a good non UPF one that is often on offer), spaghetti and cheese for a low effort quick bolognese, and just the right amount for 3 people. You could add cherry tomatoes and bagged salad if you have it.
Ive never used a delivery app and never will because it's a very exploitative business model, charges huge fees to the restaurant, low pay and lack of employment rights to the delivery person and even more expensive than ordering direct.