There was never any questioning Jet2 heading towards the south-west eventually and Bristol was always going to be the prime contender, but slot/overnight parking caperbility and competion from the likes of EZY and TUI was enough to throw the spanner in the works to maybe see a CWL or BOH operation prop up first - frankly none of those are quite such an issue for BRS now.
Reference EZY supposedly going up to 18 aircraft pre-pandemic, was that not on the basis of them having acquired Thomas Cook slots? I'd be surprised if they even maintained that into 2021 anyhow as EZY will absolutely not be anywhere up to 2019 levels again any time soon.