Woke up thinking about the combinations and meanings of “fuck” and “shit” and, no, I don’t remember what I was dreaming about to bring on those half-awake musings.
My conclusion, however, is that “shit-fuck” refers to a mess but “fuck-shit” refers to a person who makes a mess. Eg. Which one of you fucking fuck-shits is responsible for this complete fucling shit-fuck?
It can get a bit confusing when someone is a mess. But, even then, it’s probably better to refer to their “shit-fuck of a life” or to refer to whatever interaction with them as “a total shit-fuck” than to they themselves as a “shit-fuck.” Tho they may well be.
Are the dashes necessary tho? I don’t know.