You've got to wonder about that data. It says Birmingham-Milan was one of the most profitable routes in 2019 but in the same breath, that Flybe discontinued services on it in October 2019. Now I think we all could say that Flybe 1 did some crazy things and some might say Flybe 2 isn't far behind.... But closing a highly profitable route (if that data is correct) is quite strange.
The other thing that the data doesn't account for is the Air France blocked space agreements on CDG flights and the tour operator block space on routes like SOU-VRN. The remaining seats on sale via Flybe.com of old were generally at much higher fares than the "wholesale" prices and so if you take the CAA pax figures and apply the high price at which only a small proportion of seats were sold, you can get some skewed answers from this data. Flybe 1's internal accounting and reporting was so poor that it's quite possible Flybe 2 will fall into the same trap though!