They do. Even before Covid they were reducing their presence at Luton
https://www.flyblueair.com/en/gb/int...ing-march-1st/
Starting with March 1, 2021, Blue Air will operate direct flights to 13 key destinations in Europe from Avram Iancu International Airport in Cluj Napoca. The new destinations that will be operated from Cluj are: Amsterdam, Barcelona, Brussels, Dublin, Hamburg, Cologne, Larnaca, London, Madrid, Milan, Paris, Rome and Stuttgart.
At the same time, Blue Air announces that all flights to London will have London Heathrow as their destination airport, and all flights to Paris will have Charles de Gaulle as their destination airport.