Regarding staffing, I do believe BA were trying to ramp up recruitment once the winter 2021 season (in aviation terms, not literally seasonal terms) started, however, US gov's decision to reopen in November definitely came as a welcome surprise to many including so-called aviation analysts. Merely a week or so before the announcement was made about reopening in November, there was a lot of whisper and talk going round in the media that a border reopening may have not come round till perhaps the start of 2022 summer season on 27th March. Even Grant Shapps wasn't briefed in advance about it despite "high-level talks" with his US counterpart since 2020 lol - appalling, how rude of US gov! (Sarcasm intended lol)

Then of course once the reopening was confirmed for November, it all then became a bit of a frantic rush of which the effects we are truly seeing now as countries are opening up almost like dominoes one after the other.

Having said that, the furlough scheme lasted until September 30th 2021 in the UK, they quite easily could have kept on a huge chunk of staff, who I'm sure would've been happy to be furloughed and ready to come back shortly after. They didn't need to coerce (some would say virtually blackmailed) so many thousands of former staff and then get themselves into a staffing bottleneck! I believe the main issues relating to staffing are the delays in security clearances for airside passes which was slow pre-pandemic, never mind now. From what I hear, they have the right numbers in the pipeline now (hence why public recruitment for say ground staff and cabin crew has stopped - bar existing LHR and STN pass holders) but delays before they can actually be "ready" to start their jobs. I suspect this will persist through the S22 flying season and improvements should be seen (gradually) from W22 season.