My point was about the fact, and yes it is a fact, that across the UK different Trusts use different contracts. This means different hours, shift patterns and pay.
It also means different opportunities to study for the next stage. It can be assumed that not having to undertake night shifts makes study a lot easier.
You are almost certainly right that a busy F1/F2 gives plenty of opportunity for experience. However acceptance for specialist training is not based on experience but on exams. The (worldwide) competition is such that rather than stay that extra 15 minutes to ensure that the crisis is dealt with, an F1/F2 benefits from watching the clock and rushing back to open the books.
It can be done. DS knows an overseas medic who took his F1/F2 in the same deanery and, in part because this is what he was there for, very much limited his life to work, eat, sleep and study. He now has a prestigious training position with a top London hospital. One of the people DD knows who was randomly allocated the deanery when their points should have guaranteed them a top choice of London placements, has opted to live in hospital accommodation in a small town even though most choose to commute from a nearby city. I assume they too have decided to give absolute focus to the next stage and passing those exams.
However the NHS is asking a lot for a group whose University careers were strongly impacted by Covid. DD loves her work and is willing to go that extra mile. Equally she knows that she functions best if she can maintain a good work life balance. She has dug deep, is playing competitive team sport and has a good group of friends, mainly non-medic, so has some understanding of local patients and their attitudes. It might well make her a better doctor. But these are not the qualities the NHS prioritises.
DDs last week was not meant to be an illustration of long hours, just of the irregularity. At one point she had ten days on the trot including several longs. And yes staff shortages and having to cover are frequent. In her first F1 placement they lost over 10% of their numbers quite quickly. And on one night, no Registrar turned up and a busy hospital in a very deprived areas was staffed overnight by one F2 and two newish F1s. (They were given numbers to call - luckily there were no major crises.)
It is easy to say that F1/F2s could do more. It is pretty obvious though, that most are doing enough. And indeed that the ability to set boundaries and look after yourself is probably a key skill over a long career. Perhaps the NHS should instead be looking at their own approach. Are they worried about the fact that so many feel they have no alternative but to look overseas? Does the NHS really think that they themselves do better by giving equal consideration to those from overseas, even though they might not have had to go through the demands of a busy F1/F2?