You make way less money than your peers in California and everything is still as expensive. It's a financially horrible decision if you can work in the US. If you want to work in Europe though it's pretty good. I've worked at FAANG in US and UK and am currently going back to the US for non-financial reasons. I don't regret being here but I find London to be impossibly expensive to build a family in.
On £100k London is pretty affordable, so I’m curious, how much were you making in London and what do you consider to be a required salary to start a family here? London is very expensive but I’ve not heard the sentiment that FAANG salaries aren’t enough — would be helpful to learn more specifics of your view!