The thing about believing that the schools in your school district are all excellent is a very comparative view. You think that because you know that there are also schools with metal detectors and a permanent police presence.
I don't know of any UK schools at that extreme negative end, but there is clearly a variability of state schools in the UK.
The big concern with UK schools is bad behaviour. A middle class UK suburb will not be immune from this, where a middle class US suburb will.
However, you don't have children in schools yet and you are going on a self-styled reputation of these schools, and a gung-ho American culture.
Obviously I don't know your school district, but have lived (and sent children to schools) in a top US school district (top 10, top 50 on a national scale - so really up there). I have done my duty in the classroom there (we had a rota organised by a fierce class 'mom'). TBH, I wasn't that impressed by the behaviour of the 7 year old students, with my most recent frame of reference a gritty primary on a Surrey council estate. In general, I was very underwhelmed with the educational system there, where it was very much rote learning to a homogenous mass. At least in the UK, we try to treat students as individuals.
However, I do think they were able to make wanting to learn 'cool', and people were generally nice to one another. When we moved to Surrey, I couldn't contemplate sending my DS to a 40% A-C secondary school after his US experience. That was the beginning of our journey into the private sector, which frankly I have no regrets over.
The big house meant nothing to me. It was just more space to furnish, clean, heat and coool. Much more important was people-relationships, and less emphasis on changing your seasonal flags and having the correct outside lighting. I really wouldn't give a second thought the the material side of life.