At various points, several western European nations have been "democratic socialist", with varying degrees of success. Not so much of those since the end of the Cold War, but they were generally on the liberal side when it came to personal freedom. For example, the UK — and sure, the UK had The Troubles and all the associated awfulness, and the Empire for some of that period, ditto — the police forces in England, Scotland, and Wales were not (and still are not) routinely armed.

Well, yes, but the next problem to talk about is definitions. Democratic socialism is a name that's not really socialist. Socialism is state control of the economy. That's fundamentally different to creaming the top off a capitalist economy.

Now if the UK enlarges the state to the point where the NHS owns everything and all resource allocation is directed by some bureaucrats, then, sure it's actual socialism. Until then it's capitalism with a giant all-powerful anchor attached called the state.