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.
Asshole works, but its not as rude.
The bigger question is, are you honestly that much of a prude?
I actually think that depending on the context asshole is more hurtful than motherfucker. “He’s a stupid motherfucker” seems like you are just angry. “He’s an asshole” sounds like he legit is a ln awful person. Not a dominant fucker or anything. Just a dirty, unpleasant being. It is more demeaning I would say. I would be more hurt to be called an asshole than a motherfucker.