With one exception, every Sales Report counts an order in the period in which it was placed (its creation date), not the date it is delivered or picked up. That includes Gross Sales, Profit And Loss, Taxes, Meals, Packs, Fees, Conversion, First Time and the Orders Metrics dashboard.

The Delivery and Pickup reports look at the delivery/pickup records attached to orders, but those records are also filtered by the date they were created (which is when the order was placed) – the code even has the "correct" filter on the actual delivery date commented out. So if you want "what did I deliver this week", use the fulfilment/cooking reports instead; the Sales Reports tell you "what did customers buy this week".