Is there an alternative to "motherfucker" that people would actually use?
The word can have swearing but not genderisation which might be offensive (mother) nor allusions to sexual dominance (motherfucker). Nor, other possibly offensive connotations. It seems that the word is commonplace and people won't stop using it, so an alternative to the word may be useful. But the problem with alternatives, is that people might not use them unless they carry a meaning that's attention grabbing in some way, and when it comes to this word it needs to be able to be used in either a serious (non-funny) or comedic way.
I use buttfuck/buttfuckin' an awful lot as an adjective but not really as a noun. Come to think of it, I don't often -- oh, no, wait, when my cats are being unreasonable we do call them little assholes, but swearing at them turns it into a term of endearment anyway.
Dipshit, wanker, buttnugget, cunt, probably my top go-tos lol. I kind of love how some people just hate the word cunt.