The first thing to learn is foil cones are consumables. Damaged foil cones cannot be repaired. That sounds strange at first. When you see how much effort is put into making such a small part. However, it is not about the foil cones. They are just a means to an end. The purpose is to hit a target. Foil cones that are in perfect condition help here.
However, you will not remain perfect. They wear out or become damaged with use. This is a completely normal process. I had to learn that too. Damaged foil cones fly inaccurately. For this reason, it is important to replace them as early as possible. This applies not only to the cones but also to the fixations. Damaged fixations can also have a negative effect on the flight behavior of the arrows.
It can sometimes happen that several foil cones are completely destroyed. This is annoying, but replenishment is quick and easy with the right tool. For this reason, one should not be disturbed by destroyed foil cones. I break some almost every day too.
Here are a few impressions of what can happen.