It took 10 years for Stobart to grow the airport from zero to 2 million pax p.a. From where SEN is now and being able to demonstrate a fair number of successful routes I don’t think it will take anything like that timescale to get back to 2019 levels and beyond. Does depend one one key factor though. Demand must challenge capacity in the south-east. Airlines must want growth and feel restricted elsewhere to come.
Way too premature to write the airport off.