there is now no longer a shortage of slots at LGW
There is for anybody who wants to operate post this winter in the way things currently stand, unless incumbent airlines are willing to lease them out. Even that may not be an attractive proposition to some carriers.
There's little doubting LHR is the clear front-runner when it comes to any kind of long-haul, except maybe the traditional Carribean, Mexico, Florida leisure market, but even that's somewhat being proven wrong. It's often puzzled me why there is such a focus on LGW for long-haul when LHR is not an option, and why STN has been unable to take it's fair share of the overspill.
Unless there is a code-share or alliance partnership (Qatar with BA/IAG for example) which, at least before the pandemic, exists at LGW. Otherwise I see no real strategic value of LGW over STN for alot of the long-haul business, where the determining factor ought to be a matter of cost and local demographic. Prestigiousness probably has a part to play, but that is fundamentally misunderstood.
The fact EK have cancelled 2 of 3 daily A380's to LGW and plan to retain a daily B777 to STN into next summer though is somewhat of positive where STN is concerned, though I suspect the cargo element is a factor there.