As someone living in SE London and having traveled to many places around the world, I’m not sure I can agree with the “significantly lower quality of life” part, although of course YMMV as to what you are looking for. London has its share of problems like anywhere else, and I would say things are in some ways not as good as they were (could just be me getting old) but it is still on balance a very privileged place to live in terms of access to work, facilities, entertainment, food options etc. I have not seen many places that can compare, let alone be better for my needs.