  Twisted van der Waals materials have become a paradigmatic platform to
realize exotic correlated states of matter. Here, we show that a twisted
dichalcogenide bilayer (WSe$_2$) encapsulated between a magnetic van der Waals
material (CrBr$_3$) features flat bands with tunable valley and spin flavors.
We demonstrate that, when electron-electron interactions are included,
spin-ferromagnetic and valley-ferromagnetic states emerge in the flat bands,
stemming from the interplay between correlations, intrinsic spin-orbit coupling
and exchange proximity effects. We show that the specific symmetry broken state
is controlled by the relative alignment of the magnetization of the
encapsulation, demonstrating the emergence of correlated states controlled by
exchange bias. Our results put forward a new van der Waals heterostructure
where symmetry broken states emerge from a genuine interplay between twist
engineering, spin-orbit coupling and exchange proximity, providing a powerful
starting point to explore exotic collective states of matter.
