Following this lead, MC should remain just a waitress. But no sex with anyone. Since it's just about "a waitress who has to pay house rent", sex is not needed - working as a waitress is enough.
There is one meaning. If it's just about bills and rent, working as a waitress will suffice. If the MC wants more money, he has to do more "bold" things. The bolder, the more money.
Everything can be justified. We do not know what motivation MC will have in erotic experiences (and whether she will have any motivation at all, or whether it will only be a compulsion against her will), but if her motivation is money, then consent to any, even the most unnatural, perversions can be explained in a simple way - the desire to earn more money. When MC enters the erotic world (and gets more and more money for it), she will realize that the more fucked up activities she performs, the more money she will get from it. And for the most unnatural "sessions", she will get the most money.
And if there is no monetary motivation, because MC's fate will depend on perverted degenerates and not on herself and MC will have nothing to say, then the matter is even simpler - there are no limits to perversion. The only limitation is the imagination of the degenerates that the MC encounters in the village (and their minds can be really sick).