So a lot to unpack here.
i live abroad so understand what it is to be away from family….some of my thoughts….
You visa isn’t guaranteed. The company may be able to provide a smooth transition but the US government sure won’t. The have been actively discouraging immigration to Silicon Valley. Very difficult to get a visa for you let alone your husband.
You husband working will take time and he will have to enter the country on a working visa so you may be split for while as he waits at home for his to be granted (if it is). If he has applied for an working visa and enters the US they could deny him knowing his true intentions. . Again visas are hard to come by - I wouldn’t count on this.
SF is extraordinarily expensive. A lot of people with a ton of money live there so rent and costs are very very high. It is also difficult to find somewhere to live as housing is in high demand. Your salary may seem high but I would figure it out on an expat calculator - you won’t be as well off as you think.
It would be naive to not consider the current political situation. There is no amount of money that you could pay me to live there right now. None. Gun crime is real.
Culturally it is VERY different to the UK and a lot of people struggle to settle. I would suggest you join an expat grouo online. Homesickness is a killer and shouldn’t be underestimated.
The city has extreme wealth and extreme poverty. There is a serious homeless problem including vast tent cities.
Weather isn’t awesome - normally around 15 and misty (England anyone? 😂).
Make certain you get an amazing amount of healthcare coverage through your package. Otherwise any illness could be thousands out of your pocket even for things like deductibles.
Public transport is poor so you will each have to have a car as you will need to drive everywhere. Car insurance is much higher in the US than in the Uk. We are talking like $500 a month EACH. And you will have to change your UK license for a California license almost immediately.
Check your holiday too. Standard is two weeks a year and you can’t take any until you have accrued it. Work culture is different and Americans have an always on mentality. You may get personal days a year for example which are used as sick days if you get ill.
I think you really need to think about the whole picture as you seem a bit stars in your eyes for a lot more money and big adventure.