We are quite capable of generating our own culturally-specific name-based slurs in the UK . . .
(Spoiler: tongue-in-cheek!)
. . . and USA-based versions just Do. Not. Travel.
UK "Karen" is nowhere near USA "Karen". Both might be stereotypically white but even that does not have the same resonance / baggage on both sides of the pond.
It just does not work.
Going back a few years, "Annabel" was a "Sloane Ranger" stereotype and "Tim Nice But Dim" her donkey-brained, braying consort.
How does that resonate in the USA??
More than anything the insistent pummelling of USA Cultural Imperialism in memes like "Karen" annoys me more than anything.
Just piss off, Yanks! Keep your classist, racist stereotypes to yourself - we demand diversity of bigotry!
And reparations for all that tea you so inconsiderately tipped into the harbour at Boston.
And proper spelling from now on, you U-phobic wazzocks!