  The magnetic Otto thermal machine based on a two-spin-1/2 XYZ working fluid
in the presence of an inhomogeneous magnetic field and antisymmetric
Dzyaloshinsky--Moriya (DM) and symmetric
Kaplan--Shekhtman--Entin-Wohlman--Aharony (KSEA) interactions is considered.
Its possible modes of operation are found and classified. The efficiencies of
engines at maximum power are estimated for various choices of model parameters.
There are cases when these efficiencies exceed the Novikov value. New
additional points of local minima of the total work are revealed and the
mechanism of their occurrence is analyzed.
