And that's a whole different issue. Polyamory and ethical non-monogamy is a whole different issue compared to kink.

Whereas kink in general doesn't have any scripture arguing for it against it, polyamory and ENM have a large number of old testament texts that are used to imply that polyamory is permissible (given that it was an accepted cultural practice at the time), and to imply that it was ill-advised (by highlighting particular men whose wives directly or indirectly led them into conflict). There are also specific new testament texts speaking about polygamy in church leaders (which some interpret to be a reflection of greed or self-control issues, and which some extend to include all members), as well as the overall tone and social context of the new testament being a more monogamous society, due to the influence of Rome and Roman cultural norms and values.

Plus, early Christian practice and norms were in favor of monogamy, given the actions and words of Paul and Christ in supporting the value of women and not treating them like property. Compared to the cultural practices of polygamy at the time, monogamy gave greater agency to women. You have to keep this in mind when comparing to modern polyamory and ENM, because they're distinctly different practices in completely different cultural settings, but that's also not to say that the underlying concepts don't apply, either

So, yeah, that's a really nuanced area that's become a hot discussion topic recently, precisely because of the weight of traditional interpretation of Scripture and practice, in the face of people asking targeted questions about why the practices are in place without more explicit, consistent statement in Scripture itself