Can the value of fidya be set at 220 millimes, which is equivalent to a quarter of the Zakat al-Fitr, estimated at 870 millimes, knowing that the price of a loaf of bread is 240 millimes, and that Allah says: "from the average of that which you feed your [own] families"?

The obligatory fidyah (expiatory payment) is approximately equivalent to 750 grams of food. It must be given as food, not its monetary value, unless there is a justification, such as extreme need in another place, or for giving it to an agent who will purchase food with it. This also applies to Zakat al-Fitr.