I lived in HK for 14 years from 2008-22. My DC were both born there. I would agree with some of your pros and cons but not all. In terms of understanding the reasons for people leaving, the reasons are different for locals and expats. Locals who emigrated to UK did so largely because of the NSL and the greater influence of the mainland government over HK. It’s nothing to do with small flats or heavy homework loads although that might be what they say to avoid getting into a political discussion . Expats who left left largely because of the ongoing covid restrictions. This seems a bit crazy with hindsight because everything was normal a year later but there was obviously no way of knowing that at the time. Regardless, expats are starting to move there again although they tend to be younger families. Not many people move there with older ( secondary) dc but that’s always been the case.
In terms of uk being gentler on children, ha ha ha. Expat parents in HK are way way more relaxed about academics/ ECAs and less sharp elbowed than prep school parents in the UK. In terms of ECAs, Grassroots kids sport is pretty well developed in HK. I know what you mean about certificates in shopping centres but that’s easily avoided. Once you tap into the expat community you’ll discover a load of more informal stuff. In terms of overall safety, yes, but also most of the Uk isn’t that crime ridden and populated by gangs ( also to be clear there are gangs in HK, but your dc are unlikely to be recruited due to insufficient proficiency in Cantonese 🤣). There’s an opposing argument that because it’s safe, HK teenagers get too much freedom to just hang around at night at relatively young ages and that that produces problems of its own. However, it is great just to be able to let your 11/12 year old get taxis on their own.
Better food at better prices- not really tbh. Supermarket food is a lot more expensive then UK. Restaurant food can be cheaper but realistically the places you’ll go to won’t be.
Domestic help- migration is a reality of the south East Asian labour market and the situation is more complicated than pp have implied. Without denying that exploitation and abuse exist, with the right employer it can be a mutually beneficial situation and tbh if you’re both working it’s essential unless your dc are secondary age because there’s no other form of childcare unless you sponsor a nanny who will come to HK and work for you. It’s not a frictionless system by any means but it made my life a lot easier. Use Fair Employment Agency to hire as then you know the helper isn’t being charged recruitment fees which is actually the main problem in the system as they start off in debt.
Politically, unlikely NSL eduction will become a big part of international schools. There may be like a 1 hour session on it but it would be too hard to incorporate, say, NSL approved Chinese history, into a curriculum that doesn’t even have Chinese history in it.
HTH