Yes for sure regarding EasyJet, they operated BHX-JER one season only (2021) no doubt to cash in on the staycation boom. I used the service twice and loads were healthy although not stellar! Seem to remember it was a W pattern with MAN based crew
Not so sure about Jet2 and when they started BHX-JER, it has only just been chopped for 2023 and they're still flying to JER from EMA, STN, LBA and NCL next summer. So perhaps they do have a better use for the aircraft as clearly BHX-JER didn't work for them. Hopefully Blue Islands alone will satisfy demand.