  Fundamental studies of the interaction of chiral light with chiral matter are
important for the development of techniques that allow handedness-selective
optical detection of chiral organic molecules. One approach to achieve this
goal is the creation of a Fabry-P\'erot cavity that supports eigenmodes with a
desired electromagnetic handedness, which interacts differently with left and
right molecular enantiomers. In this paper, we theoretically study chiral
Fabry-P\'erot cavities with mirrors comprising one-dimensional photonic crystal
slabs made of van der Waals As$_2$S$_3$, a material with one of the highest
known in-plane anisotropy. By utilizing the anisotropy degree of freedom
provided by As$_2$S$_3$, we design Fabry-P\'erot cavities with constitutional
and configurational geometrical chiralities. We demonstrate that in cavities
with constitutional chirality, electromagnetic modes of left or right
handedness exist due to the chirality of both mirrors, often referred to as
handedness preserving mirrors in the literature. At the same time, cavities
with configurational chirality support modes of both handednesses due to chiral
morphology of the entire structure, set by the twist angle between the optical
axes of the upper and lower non-chiral anisotropic mirrors. The developed
chiral Fabry-P\'erot cavities can be tuned to the technologically available
distance between the mirrors by properly twisting them, making such systems a
prospective platform for the coupling of chiral light with chiral matter.
