interesting question regards Jet2.
their winter operations appear to have been successful but I think they have (not entirely but largely) filled a gap left by BA this winter, pre covid (and I would suspect winter 21) BA operated ski and Lapland flights, this winter without them I think LS have been smart plugging the gap but moving forwards, with LS having such a strong operation further North in the U.K. and with strong competition at LGW from U2, BA, TOM and W6 I’m not sure it would be wise for LS to try and break into the LGW market.
The Jet2 flights were charter flights operated on behalf of tour operators that tend to go to the cheapest bidder. In the past, these flights were operated by the likes of Germania, Small Planet and Enter Air. I doubt Jet2 even made any money on them.