I used to think like this, but my attitude changed over the years. I'd take a sabbatical from work , do a 3 month stint in the destination country. The romantic view often doesn't fit the reality. You'll be an immigrant in a new country, even if most people look more like you, its still a big culture shock.
It was going to South Africa in my 20's and meeting white Africans that has changed my mind. They felt they were truly African and I had a lightbulb moment, why do these whites have no problem calling themselves proud Africans and I struggle to call myself British?
All over the globe white people of European origin ( through white supremacy ) have no problem calling themselves, American, Australian or African , yet Black people who originate from example Nigeria or Jamaica have had relationships which Britain for 100's of years, but struggle to call themselves British.
Nigeria history since 1861 was in large part British soil, Jamaica even longer, since the 1600's.
Most black people in this country have shed blood , sweat and tears to call themselves British, why give that up?
The Windrush scandal shows the contempt most in this country have to calling black people 'truly' British, but fuck them!
Yes, its shit here, yes the weather is shit and we currently have a goverment that is the same as the National Front or the BNP , but its our home , like it or not. I'm not going anywhere.
I'm trying to teach my kids they have every right to be here and call themselves British and when some racist prick tells them they aren't British, they should reply the MILLIONS of white South Africans are actually Dutch and British should fuck off home then? I then tell them they should tell White Afrikans that to their face and see what happens.
On the flipside, if you can build a better life somewhere , go for it! If for example I could double my salary in a new country or some other amazing opportunity, I would go for it. But I wouldn't leave because I was just fed up with the UK.