I doubt Jet2 would come to DSA. Why would they?
It's unlikely to happen, but why wouldn't they?
From Doncaster, LBA is 1.5 hours away, and East Mids is an hour. From Lincolnshire, they are even further.
DSA to LBA is 55 miles. Jet2 have bases at Blackpool and Manchester (57 miles apart), and Glasgow and Edinburgh (48 miles apart).