I thought that was a Becky?
“Becky” is the girl who Beyonce thought wanted to take away her husband. The line in a song was “Becky with the good hair,” so people who wanted to racialize things wrongly assumed that “Becky” was white and applied it to young white women in general. I guess “Becky” and “Karen” are in competition, but “Karen” is more specific and may have more staying power. There’s a generational aspect, too - “Karen” is over 35 or so, and “Becky” is considerably younger than that.