This is all extremely vague.
You're unhappy why? Remember the expression 'wherever you go, there you are'. Are you sure that the idea of greener fields is just a distraction from deeper problems which would follow you anywhere in the world?
And when you say "Our professions could move elsewhere easily" do you mean WFH for your British employers, earning a British salary which go further there? Sounds great, but many employers insist you be resident in GB for tax, legal and other reasons. If you mean to work locally, then chances are you'd need to speak the language fluently, get your credentials recognised, have the legal right to work there and so on.
Also, you speak of lower costs of living. well, many countries are cheaper than Britain, but salaries tend to be correspondingly lower too. And higher energy prices is a global thing, not a British thing, though you might not realise that to read MN.
As for 'happier way of life', again my point above that moving somewhere else might not magically make you happier. Plus, what is it that makes you happy? Happiness is in the eye of the beholder.