What this article highlights is that Open Access mandates, such as the Plan S, can intervene into relations between researchers, libraries and publishers in ways that are non-agnostic with regard to publication formats, licenses applied and business models. To the extent that the capabilities to comply with mandate guidelines are likely distributed unequally across stakeholder groups, academic disciplines and geographic regions, the impacts of Open Access can also be expected to involve differential, dissimilar trade-offs for authors, publishers and libraries. This paper also reminds that closed access and Open Access are not necessarily diametrically opposed concepts, but theoretical, discursive constructs with multiple models in between that comply to different degrees with specific Open Access policies and can have divergent short- and long-term effects on publishing choices, e.g., in terms of academic freedom, and market development.