I don’t think you are missing out, since in my experience you usually only find “pub” friends to drink with, who often have unhealthy drinking habits and don’t become actual friends (albeit I’m faux British: in New Zealand!). Any activity (sport, hobby, work) where you hang with locals gives you the chance to make healthier relationships.
For anyone looking to make friends in a pub, you want to find a pub that is social. Some signals to look for: (a) a very wide range of ages that go there, (b) casual drinkers who are there to socialise rather than get drunk, (c) a single woman can drink at the pub comfortably without getting hit on, (d) not heaving full but rarely empty, (e) no loud music - or even better no music - if any live music it is quiet enough to talk over, (f) not a “popular“ place but a place for locals, and (g) it “feels” like someone’s house rather than a bar. That style of pub is dissapearing, and they are hard to find in large cities, but they do exist and they have a completely different culture.
Edit: if anyone from the Isles can comment on their take on this, I would appreciate it.
True in the past, but a non-issue these days, especially with younger colleagues.
> Also, being "white" helps, I think
Maybe in very provincial communities in parts of the country but not in the major cities - at least not since the 90s onwards. If anything I'd say the UK is one of the more open minded countries I've seen.