That's a lot to unpack my dear, but first let's just give you a star for mansplaining to a woman what a sexist joke should or shouldn't look like, congratz: ⭐
Second the Karen jokes are made in a proper context and do not apply to the whole of white women as a demographic. I have absolutely no beef against those jokes, because they deserve a proper context, are about women in a somewhat position of power (aka white women, benefiting from white supremacy in many ways, class included). They're not made in a vaccum to portray 51% of the population in a certain way, they deserve a time and place to be made and are more often than not justified and warranted.
However, implying, that all women (aka, again 51% of the goddamn fucking population) are such strange, alien, insecure, emotional and hysterical creatures prone to create couple fights out of clearly hypothetical situations far removed from really such as the one implied on that tweet, because "LOL WOMEN BE CRAY AHAH THAT'S FUNNY INNIT?" is just insulting, demeaning, and incredibly othering. This is what a sexist joke looks like, and I'll give it to you, it isn't an obvious one, but it is one still. I sure do hope that my more than 30 years of experience living as a woman can somehow trample your astounding amount of zero years of experience living as a woman, but somehow it feels like it won't even make a dent.
But please, do keep telling me what is and isn't okay on a subject that doesn't affect you personally in the slightest, I'm all ears.